The World of Protozoa, Rotifera, Nematoda and Oligochaeta
Euchlanis
Euchlanis Ehrenberg, 1832 (ref. ID; 7815)
Class Monogonontaet: Order Ploimida: Family Euchlanidae (ref. ID; 6806)
Synonym Dapidia Gosse, 1887 (ref. ID; 3688)
ref. ID; 1663
Dorsal plate the same size of larger than the ventral plate. Ventral plate flat, dorsal plate arched and convex, sometimes keel. Lateral sulci without a flange. Foot with two or three obscure segments. Toes usually slightly fusiform. (ref. ID; 1663)
ref. ID; 1923
Myers (1930) proposed to reduce the genera Euchlanis, Dapidia, Dipleuchlanis, and Tripleuchlanis to subgenera of the genus Euchlanis, but in writing continued to use the names in the manner of generic names. Dipleuchlanis and Tripleuchlanis are separated on the basis of the structure of the lorica. There are 2 species of Dipleuchlanis, and 1 of Tripleuchlanis, in brackish water. Dapidia was distinguished by the absence of the minute comb of teeth near the tips of the rami. Dapidia and Euchlanis each contain species with and without ventral plate and lateral sulci. It is probably preferable to leave Dipleuchlanis and Tripleuchlanis as genera and combine Dapidia with Euchlanis as done by Wiszniewski (1954). Common in littoral, but some species may occur in plankton. Length of dorsal plate up to 500 µm. (ref. ID; 1923)
ref. ID; 1934
Brachionid rotifers with a retractile head, loricate body, truncate in front and rounded posteriorly. Dorsal plate arched, convex, larger than ventral, some times with median keel and flanges, and with or without a posterior notch. Ventral plate usually flat, smaller than the dorsal, and some times absent. The plates are jointed by thin flexible cuticle forming lateral longitudinal sulci. Foot with two or three joints with well developed foot glands. A pair of setae may be present at the distal end on the dorsal side of first foot joint, and are lost in preserved forms. Two toes, different size and shape, are present. Mastax modified malleate type with 4 or 5 club shaped opposing teeth in each uncus. Single eye spot. Dorsal antenna prominent, truncate with sensory tuft of cilia. (ref. ID; 1934)
ref. ID; 3246
Rotifers with illoricate, retractile head and loricate body, truncate in front, rounded posteriorly, oval or ovate in outline. Lorica of two plates, dorsal and ventral. Dorsal plate arched and convex, larger than ventral, sometimes variable in height and shape. Ventral plate nearly flat, smaller all around than the dorsal plate. These plates are connected by thin, flexible cuticle forming lateral, longitudinal and posterior sulci. Foot with two or three obscure joints; foot glands robust; accessory foot glands present. One or two pairs of long setae are situated on the dorso-distal portion of the penultimate foot-joint; they are rarely missing in living specimens, but are apt to be broken off in preserved materials. Toes two; long or short, stout or thin, fusiform or parallel-sided. Corona family type. Mastax modified malleate. The rami are roughly triangular, diminishing near the tips into acute, incurved points. The tip of each ramus carries a minute, denticular, comb-like process situated on the inside edge. There are four or five club-shaped functional teeth in each uncus that diminish in size dorsally. There are generally several non-functional accessory teeth attached to the opposing dorsal teeth near their bases. An undeveloped tooth is frequently directly attached to the outside edge of each first or ventral opposing tooth. Eyespot single, situated on, or near, the posterior end of the ganglion. Retrocerebral sac greatly developed with indications of subcerebral glands. Dorsal antenna large, truncate, with a sensory tuft of cilia in a shallow central depression. Each lateral antenna has a tuft of two or three sensory setae that emerge from small tubules, one on each side of the body in the lumbar region. The males resemble the females but are much smaller, and the alimentary tract. Including the manducatory organs are wanting. The Euchlanids are littoral rotifers living among aquatic plants of lakes and other permanent bodies of water. Food consists of diatoms, desmids, algae and particles of organic detritus. (ref. ID; 3246)
Subgenus Dapidia Gosse, 1887: Euchlanid rotifers with illoricate, retractile head and loricate dorsal plate, truncate in front, rounded posteriorly; oval, ovate or orbicular in outline. There is no true ventral plate, the membrane connecting the lateral edges of the dorsal plate being only slightly stiffened in the position of the ventral plate of the genus Euchlanis. There are no longitudinal lateral sulci. Foot with two joints; foot glands robust; accessory foot-glands present. One or two pairs of long setae are situated on the dorso-distal end of the penultimate foot-joint. Toes two, long or short, stout or slender, fusiform or parallel-sided. Corona family type. Mastax modified malleate type with prominent dorsal salivary glands. The tips of the rami are prolonged into two long, incurved, bacillar rods without denticulation the inner edges; unci with five functional teeth. Eyespots single, situated on the posterior end of the ganglion. Retrocerebral sac large and well developed with indications of subcerebral glands. The remaining anatomy resembles that of Euchlanis very closely. (ref. ID; 3246)
Subgenus Dipeuchlanis de Beauchamp, 1910: Body ovoid, much compressed dorso-ventrally. Lorica of two plates, the dorsal being concave or nearly straight, obtusely pointed posteriorly and much smaller than the ventral, which is convex and rounded behind. The cuticle connecting the two plates is in the form of a deep groove, and divides the body cavity into two unequal portions, of which the ventral is much the larger and contains the greater part of the organs. The lateral edge of the two plates are nearly parallel and somewhat elevated. The foot is short and slender, without setae on the penultimate joint. The toes are long, very slender, cylindrical, parallel-sided and slightly swollen at the bases. The head is large and is connected with the anterior edge of the lorica by a stiffened cuticular membrane. The face is inclined ventrally. The corona is of family type. The mastax is modified malleate type. The unci each have ten or more long, slender teeth. The rami are triangular and carry on the inside of each tip a very minute denticular comb. The remaining anatomy is similar to that of Euchlanis. (ref. ID; 3246)
Subgenus Tripleuchlanis Levander: Euchlanid rotifers, the only known species being marine. Lorica ovoid in shape, truncate in front, rounded posteriorly. The dorsal and ventral plates are of nearly the same size; they are connected by a pair of lateral, longitudinal sulci, on pair on each side of the body; between each pair, a longitudinal flange of stiffened cuticle extends for the entire length, giving the cross-section a bellows-like appearance. The dorsal plate has a shallow posterior emargination. The foot is stout and has tree joints; it is guarded by a cuticular shield-like process extending downward from the median longitudinal flanges. The foot glands and their accessories are very long. The toes are short, stout and parallel-sided, ending in rather abrupt points. The corona is of family type. The mastax is of the modified malleate type. There are six club-shaped teeth in each uncus; the rami are triangular and carry on the inside of each tip a minute denticular comb. The eye-spot is double and situated near the posterior end of the ganglion. (ref. ID; 3246)
ref. ID; 3334
In this genus, the lorica consists of two plates, which, in most species, is separated by a flexible membrane that forms lateral sulci. The lorica lacks spines and other forms of ornamentation. The dorsal plate is arched and wider than the ventral plate. The foot projects between these plates at the posterior end. Although the two toes are long and strong, the foot and toes together are shorter than the lorica. The mastax has malleate trophic. (ref. ID; 3334)
ref. ID; 4594
Dorsal plate with the median portion arched; ventral plate nearly flat and usually smaller. Foot with two or three segments. Toes rather long, nearly swordlike. Many species, but only a few are found in brackish water. (ref. ID; 4594)
Forms of Euchlanis with no notch on the back edge of the dorsal plate were found in certain waters. One of these is characterized by the lorica severely tapering towards for front and by its unusually wide toes. The ventral plate is complete. It is true that they have no wing-like expansions on the dorsal plate but this also holds good of some of the forms studied by Myers (1930, Pl. 16), which moreover bear an external resemblance to those from Lapland. The Lapland specimens are smaller than those measured by Myers (180-205 µm and 260-280 µm respectively), but his need not significantly affect the question of identity in a genus where the size within each species generally varies widely. Moreover, Voronkov (1912) states that the mean length of the lorica in E. alata is 252.8 µm and in the specimens from Northern Norway mentioned below (Olofsson 1917) it varied between 190 and 290 µm. (ref. ID; 1450)
Body resembles arc of a circle in cross section. Dorsal plate with or without lateral wing like expansions. No posterior notch but with little emargination in its place. Ventral plate elongate and one-half the width of the dorsal junction with the oesophagus two pairs of glands are present. Toes stout and fusiform. Myers (1930) stated that this species has seasonal or cycle "wing" development. (ref. ID; 1934)
The body consists of two plates, dorsal and ventral, the dorsal one being much the large, about twice as wide as the ventral. No keel is present on the back. In the winged form, both sides of the dorsal plate are expanded to at least two thirds the length. The posterior tip of the wing is pointed, turned slightly upward, making the greatest width. The central posterior part gradually becomes low and has no notch. At the anterior extremity a large V-shaped notch is present. The wingless form is elliptical. The ventral plate is slightly convex, elongate elliptical, its posterior broader parallel to that of the dorsal plate. The foot is large, two-jointed, with one pair of toes. A large central, anterior eye-spot is present. Both the winged and the wingless forms were collected from the littoral region of Taitaik. They are 20 per cent larger than the form recorded by Myers (1930). According to his note, various stage of "wing" development were found in this species in the acid waters of Mt. Desert Island, Maine, but the forms from Atlantic County, New Jersey, had no lateral wing-like processes. At that time, this species had been found in only four places in the world, i.e., near Moscow, Russia, Arc-en Barrois (Haute-Marne), France, and the two localities mentioned above. The present finding is probably the first record in the Far East. (ref. ID; 3063)
The body resembles an arc of a circle in cross section, and may have lateral wing-like expansions of the dorsal plate; or may be perfectly ovoid without any signs to these expansions. Intermediate forms are common with the lateral expansions just starting to form. There is no true posterior notch, but a slight emargination may be sometimes seen in place of it. The central plate is elongate and somewhat over one-half the width of the dorsal. The foot is robust and has two joints. Two pairs of setae project from the dorsal side of the first foot-joint. The toes are stout, fusiform and about one-fourth the length of the dorsal plate. The dorsal antennae are normal and the lateral antennae are in the usual position. The mastax is modified malleate type. The tips of the rami are acute and incurved with a pair of finely denticulate combs, one on the inner side of each tips. There are four stout functional teeth in each uncus, with several accessory teeth attached to the dorsal pair at their bases. At the dorsal of junction of the mastax with the oesophagus, there are two pairs of what appear to be glands, one pair of each side of the oesophagus. These may be the "sessile renflenments" referred to by de Beauchamp; they are quite large, the anterior pair being much larger than the posterior pair; they contain several large nuclei indicating their glandular structure. In the genus Calpidia the pair of dorsal salivary glands are large and originate in the anterior portion of the mastax. The small glands in Euchlanis alata, above referred to, originate at the junction of the oesophagus with the mastax and may be gastric in their function. The retrocerebral sac is large and well developed. The stomach and intestine have the usual strong constriction between them. The foot glands and this accessories are large and stout. The remaining anatomy is normal to the genus. (ref. ID; 3246)
Comments
The species, form without "wings", may easily be mistaken of Euchlanis deflexa. (ref. ID; 3246)
Measurements
Dorsal plate length 335, width 315, frontal width 160 (winged form); foot 110; toe 18 µm. (ref. ID; 3063)
Length of body 140, width 180 µm over "wings". (ref. ID; 3126)
Length of body less toes 140; width of dorsal plate 150; width of ventral plate 120; length of toes 50 µm. (ref. ID; 3128)
Length of dorsal plate 260-280; length of ventral plate 200-220; length of toes 70-100; width of dorsal plate 185-210; width of ventral plate 150-170 µm. (ref. ID; 3246)
It resembles E. triquetra with a keel, but differs in having flanges for dorsal plate, absence of ventral plate, shape of the dorsal antenna, and shape of the toes. This species also resembles E. pellucida in having keel, flanges, and absence of ventral plate; but differs by the smaller size, ovoidal shape of the body, shape of the toes, and mastax with four teeth in the uncus. These differences are qualitative and distinct. (ref. ID; 1934)
Descriptions
Body ovoid, truncate anteriorly, rounded behind and triradiate in cross section. Dorsal laterally produced into flanges, and with a dorsal median keel extending its entire length. Posterior notch absent and a slight emargination present in its place. Ventral plate absent. A thin membrane - venter joins the dorsal plate laterally. Longitudinal sulci absent. Dorsal antenna obliquely truncate with small tuft of sensory setae. Mastax with four opposing club shaped teeth in each uncus. Foot two-jointed. Two setae project from the distal end of the first foot joint. Toes are slender, parallel sided, tapering into points and nearly 1/3 length of dorsal plate. (ref. ID; 1934)
Measurements
Length of dorsal plate 238; width of dorsal plate 196; length of toes 70 µm. (ref. ID; 1934)
The body is much laterally compressed, very high dorso-ventrally and has a central keel extending the entire length of the dorsal plate. There is no ventral plate, and the membrane, taking the place of it, is joined directly to the sides of the dorsal plate without the intervention of longitudinal sulci. Only the extreme posterior portion of the venter is cuticular. The foot is obscurely two-jointed and two setae project from the dorsal side of the first foot-joint. The toes are long, parallel-sided and quite slender. The dorsal antenna is unusually large in diameter and obliquely truncate; it bears the usual tuft of sensory setae in a shallow central depression. The lateral antennae are normal and in the usual position. The mastax is of the modified malleate type; the rami are stout and triangular, more robust at the tips than in the other species; there are a pair of very minute denticulate combs, one on each ramus just inside this tips. The two opposing ventral teeth of the unci are very stout, followed by four more slender teeth without any accessories. The remaining anatomy is normal. Euchlanis callysta is rare, always very transparent, seldom with coloring matter in the stomach or intestine; it swims through the water very rapidly and is in constant motion. (ref. ID; 3246)
Type locality
It has been collected in Atlantic Country, New Jersey and on Mt. Desert Island, Maine, in permanent bodies of acid water, ranging in pH from 6.4 to 6.8. (ref. ID; 3246)
Measurements
Length of dorsal plate 170; length of toes 50; width of dorsal plate 80; depth of lorica 65 µm. (ref. ID; 3246)
The dorsal plate is variable in cross-section, it may be high and obscurely triradieate, or round. The middle portions of the lateral edges may, or may not be, pinched in and extend downward below the venter. The sides of the dorsal plate are connected by a flexible membrane somewhat stiffened in the position of the ventral plate as in the genus Euchlanis. There are no lateral, longitudinal sulci. There is a wide V-shaped notch in the middle of the posterior margin of the dorsal plate. The foot is slender and two-jointed; it carries two pairs of long setae on the dorsal side of the first foot joint. The toes are long, slender and parallel-sided, ending in rather abrupt points. The mastax is of the modified malleate type. The tips of the rami are drawn out into long, bacillar rods, without denticulate combs on the inner side of the tips. There are five slender, opposing teeth, clubbed at their tips, and two to three accessory teeth in each ramus. There are a pair of prominent dorsal salivary glands attached to the mastax near its anterior part. The remaining anatomy is normal. (ref. ID; 3246)
Comments
Dapidia calpidia resembles Dapidia deflexa by the presence of dorsal salivary glands and the same type of mastax; it resembles Dapidia pyriformis by the presence of dorsal salivary glands and the same type of mastax and, in some cases, the same type of dorsal plate with the lateral edges pinched in. It differs from them by having long, slender toes and by the presence of a distinct posterior notch. This may be a form of the species described by Gosse as Dapidia stroma. What there is of his description fits fairly well. As the description in the Supplement is in sufficient for a positive determination, no mention being made of anything but the lorica, the specific name Dapidia stroma is not used here. Dapidia stroma has never been found since and it seems advisable to wait for further information on the species before definitely deciding that it is the same species as Dapidia calpidia. (ref. ID; 3246)
Measurements
Length of dorsal plate 250; max. width 210; toes 90 µm. (ref. ID; 2277)
Length of body 240; length of toes 90 µm. (ref. ID; 2385)
Length of the dorsal plate 280; width of dorsal plate 220; length of toes 120 µm. (ref. ID; 3246)
This species can be diagnosed readily by the shape of the feet and the form of the trophi. The median portion of the feet is narrow and the end has a sharp claw. The shape of the rami of the mastax is similar to that of Euchlanis dilatata lucksiana, but the posterior margin of the right ramus is hollowed. (ref. ID; 1847)
Dorsal plate ovoid, without a posterior notch but with a shallow emargination in its place. Lateral edge of dorsal plate thickened at the plate of attachment with ventral plate. Longitudinal sulci are absent. Foot stout and two-jointed. Toes short, stout, fusiform and ending in tips that appear papillose in dorsal view. Mastax with five slender club shaped teeth in each uncus. A pair of prominent dorsal salivary glands that lie attached to anterior part of mastax. (ref. ID; 1934)
The body resembles the arc of a circle in cross-section. The dorsal plate is ovoid, constant in shape and without a distinct posterior notch, although there may be a shallow emargination in plate of it. The lateral edges of the dorsal plate are connected by a flexible membrane somewhat thickened in the position occupied by the ventral plate in the genus Euchlanis. The posterior portion of this are is of hardened cuticle. There are no lateral longitudinal sulci. The foot is stout and two-jointed; it carries two pair of long setae on the dorsal end of the first foot joint. The toes are short, stout and fusiform in shape, ending in tips that appear almost papillose in dorsal view. The dorsal and lateral antennae are normal. The mastax is modified malleate type. The tips of the rami are down out into long, slender, bacillar rods, without denticulate combs inside the tips as in Euchlanis. There are five slender, opposing teeth, clubbed at the tips, and two to three accessory teeth attached to the bases of the dorsal teeth in each ramus. There are a pair of prominent dorsal salivary glands attached to the anterior part of the mastax. The remaining anatomy is normal. (ref. ID; 3246)
Comments
Pejler found in a plankton sample a specimen of a type which he somewhat doubtfully classify as E. deflexa. It conforms with Myers' (1930, Pl.21) illustrations regarding both the shape of the dorsal plate and the fact that the ventral plate is incomplete. The toes, however, are proportionally longer and narrower in the specimen, which is also considerably smaller than the one described by Myers (length of the lorica 157 µm and 280 µm respectively). (ref. ID; 1450)
At first glance, this species can easily be mistaken for the form of Euchlanis alata without the lateral wing-like expansions of the dorsal plate. Both are robust animals with stout toes and foot-glands. If it be remembered that Euchlanis alata has a normal, well-marked, ventral plate with lateral flanges and longitudinal sulci, and, that the type of the mastax is different from Dapidia, there will be no confusion between the two species. (ref. ID; 3246)
Measurements
Length of dorsal plate 280; length of toes 90; width of dorsal plate 125 µm. (ref. ID; 3246)
Body is ovoid. Dorsal plate variable from low arc of a circle to a high triangle in cross section, posteriorly with a deep inverted U-shaped notch; ventral plate nearly of the same size as the dorsal with longitudinal sulci. Mastax with four opposing club shaped teeth in each uncus. Foot slender and two jointed with a pair of setae at the distal end of first foot joint. Toes, blade like and fusiform. (ref. ID; 1934)
This species varies considerably in size and shape not only in dorsal and ventral views but also in cross sections, the dorsal arc being high or low. The anterior end and the posterior notch which is shaped like an inverted 'U' are characteristic. It is large and has a characteristic shape. (ref. ID; 2715)
General shape of body ovoid, truncate anteriorly, rounded posteriorly. Dorsal plate variable in height and shape of cross-section, varying from the low arc of a circle to a high triangle. Ventral plate nearly as large as the dorsal all around and is slightly constricted anteriorly at the opening for the head, joined to the dorsal plate laterally by membranous, longitudinal sulci. Rounded posterior of the dorsal plate divided medially by a deep elongate notch shaped like and inverted 'U'. Foot slender and two-jointed. Toes about one-third the length of the dorsal plate, blade-like and fusiform in shape. (ref. ID; 3180)
It is triangular in general shape; there is a small, nude apical area enclosed by the circumapical band which is reduced to a row of long cilia. On the dorsal part of the middle portion of the apical area are situated two prominent tubular, papillose prominences, at the tips of which are the duct openings of the retrocerebral sac. Near these prominences, and on the outside of each, is a small tubule from which emerge a tuft of sensory setae. On the anterior sides of the head are two arcs of long cilia specialized for propulsion they resemble auricles but are not retractile. The buccal plate is covered with very short, close-set cilia and the mouth is at the lower extremity. The dorsal and lateral arcs of the buccal plate are strongly developed. The laterals joining under the mouth. Above the dorsal arc and below the apical area is a transverse row of long cilia disposed into three tufts on slightly prominences. The general shape of the body is ovoid, truncate anteriorly, rounded posteriorly. The dorsal plate is variable in height and shape of the cross-section, varying from the low arc of a circle to a high triangle. The ventral plate is nearly as large as the dorsal all around and is slightly constricted anteriorly at the opening for the head; it is joined to the dorsal plate laterally by membranous, longitudinal sulci. The rounded posterior portion of the dorsal plate is divided medially by a deep, elongate notch, shaped like an inverted U. When observing the posterior notch, the microscope should be focused on the anterior edge; by focusing down from this point, the posterior edge of the flexible membrane connecting the lateral edges of the notch well be seen. On plate 12, figure 5, the stippled area represents the flexible, connective membrane, and figure 6 shows a cross-section at the point A. This membrane appears to allow a certain amount of lateral expansion to the posterior portion of the dorsal plate. The foot is slender and two-jointed, and a pair of long setae protrude from the distal margin of the first foot joint. The toes are about one-third the length of the dorsal plate and are blade-like and fusiform in shape. The dorsal antenna is prominent and truncate; it has a small tuft of sensory setae in a hollow central depression. The lateral antennae are in the form of small, projecting tubules, from each of which emerges a sensory tuft of setae; they are constant in shape throughout the genus. The mastax is modified malleate in type, (sub-malleate of Hudson & Gosse). The unci have four diminishing, opposing, clubshaped, functional teeth, resting in depressions between the ridges of the rami. The large ventral teeth each have a rudimentary tooth attached for almost the entire length. There are several minute accessory teeth attached to each of the functional dorsal teeth near their base. The rami are triangular and the basal apophysis is large. The tips of the rami are abruptly reduced to very acute points carrying on the inside of each a minute denticulate comb-like process. The fulcrum is short, stout and plow-shaped. The stomach, as is usual in the genus, is shapely constricted at the point of junction with the intestine. The retrocerebral sac is large and well developed; it varies in size with its state of contraction, always being larger in well nourished individuals. The foot glands are medium and three are two small accessory glands that are constant in the genus. The gastric glands, ovary, bladder and nephridial system are normal. (ref. ID; 3246)
Lorica broadly oval; dorsal plate depressed in front and arched behind. Ventral plate flat, entirely rounded behind. Freshwater species, found in estuaries. (ref. ID; 4594)
Comments
This was earlier reported by Stewart (1808) from Tibet, by Edmondson and Hutchinson (1934) from Kashmir and Ladak. Myers (1930) stated that acid-water forms tend to have long dorsal plate. (ref. ID; 1934)
The form with the deep, triangular, dorsal plate may be easily mistaken for a small Euchlanis triquetra. The differences between the two species are: The dorsal plate of Euchlanis dilatata, in lateral view, is evenly arched, without a distinct neck region; in Euchlanis triquetra, the dorsal plate is very high over the stomach, rising abruptly from a rather distinct neck region, then falling away rapidly towards the foot; Euchlanis dilatata never has a dorsal keel, no matter how high the dorsal plate may be; while Euchlanis triquetra always has a dorsal keel which may not be very evident in preserved material on account of expansion, but is always present in living animals. The posterior notch of Euchlanis dilatata is deep and shaped like an elongate, inverted U; while the posterior notch of Euchlanis triquetra is relatively more shallow and shaped like an inverted V. (ref. ID; 3246)
Measurements
The specimens vary considerably in size. Thus the length of the lorica varies between 172 and 280 µm, and that of the toes between 60 to 90 µm. In specimens from running water the width of the toes seems particularly great in proportion to the overall size, but this is natural seeing that the toes act as adhesive organs. (ref. ID; 1450)
Length of dorsal plate 252; width of dorsal plate 282; length of ventral plate 238; width of ventral plate 168; length of toes 84 µm. (ref. ID; 1934)
Length of dorsal plate 178; length of ventral plate 166; width dorsal plate 135; width ventral plate 115; toes 60 µm. (ref. ID; 2704)
Length of ventral plate 120-260; length of dorsal plate 108-205; width of ventral plate 72-135; width of dorsal plate 108-165; length of toes 51-72 µm. (ref. ID; 2715)
Length of dorsal plate 200; width of dorsal plate 119; length of ventral plate 180; width of ventral plate 114; length of toes 64; width of toes 5-6 µm. (ref. ID; 2825)
Acid water forms with long dorsal plate, from Atlantic County, New Jersey. Length of dorsal plate 270; length of ventral plate 250; length of toes 50; width of dorsal plate 130; width of ventral plate 105; depth of lorica 90 µm. Material from Newdorf, near Strasbourg, France: Length of dorsal plate 200; length of ventral plate 170; length of toes 70; width of dorsal plate 90; width of ventral plate 80; depth of lorica 95 µm. Material from Vorkommen-Zangenfrund, Altwasser des Rheims: Length of dorsal plate 250; length of toes 75; width of dorsal plate 189; depth of lorica in various specimens 90, 105, 120, 140, 155 µm. (ref. ID; 3246)
Length of dorsal plate 200-240; width of dorsal plate 110-120; length of toes 60-70 µm. (ref. ID; 3275)
Total length 200-270 µm. (ref. ID; 4594)
The corona agrees with that of the genus. The body is a moderately high arc. The dorsal plate is ovate and has a fairly deep posterior V notch. There are no lateral sulci, and the edges of the dorsal plate may be turned down for a slight distance. The ventral edges of the dorsal plate are connected by a stiff membrane. The lateral edges of the dorsal plate generally are ornamented by small bosses as in Testudinella patina. The foot is robust, fairly long, and conical. It appears incapable of movement. The toes are short, and expanded towards their distyl ends; they terminate in sharp, in-turned conical protuberances. The toes have the general appearance of dental forceps. The mastax is of the deflexa type without denticulation, and with 5 opposing teeth. The remainder of the anatomy is normal to the genus. It swims very slowly. (ref. ID; 2285)
Comments
The toes of the new species separate it from all other members of the genus. In body form it has many of the characteristics of Euchlanis deflexa, but differs from it, besides the toes in a deeper posterior notch, bosses round the lateral edges, and in a different anterior opening. It differs in most characteristics from Euchlanis contorta (Wulfert), 1939. (ref. ID; 2285)
Measurements
Length of body 230-250; width 130-140; length of toes 50-60 µm. (ref. ID; 2285)
Lorica oval with shallow posterior depression. Dorsal plate strongly convex, ventral planar. Dorsal anteroposterior keel prominent. Toes strong, pointed. (ref. ID; 1806)
Body oval shaped. The 'V' shaped notch at the posterior end of the dorsal plate is characteristic. (ref. ID; 2715)
Measurements
Length of ventral plate 172; length of dorsal plate 110; width of lorica 80; length of toe 66 µm. (ref. ID; 2715)
Length of dorsal plate 175-210; width of dorsal plate 135-155; length of toes 50-64 µm. (ref. ID; 3275)
Of the other two encountered forms without the notch on the dorsal plate one is comparatively large (the dorsal plate being 300 µm in length). It has a rather elongated lorica with a complete ventral plate that is relatively short in relation to the posterior one. On the basis of these characteristics the form must be described as E. lyra. Another feature is the swelling below the middle of the toes, which is also indicated on the illustrations in Hudson and Gosse (1886, Pl.23:1) and in Myers (1930, Pl.18:2-3), although it is in neither case described as characteristic of the species. (ref. ID; 1450)
The body is elongate and ovoid. A cross-section resembles the arc of a circle. The dorsal plate is evenly arched in lateral view and there is no posterior notch. The ventral plate is about two-thirds the width of the dorsal at its widest part, somewhat constricted neat the posterior end. The foot is slender and two-jointed and has the usual pair of long setae on the dorsal side of the first foot-jointed. The toes are moderately long, very slender and nearly parallel-sided; their length is somewhat less than one-third that of the dorsal plate. The dorsal antenna is small and bears the usual tuft of sensory setea in a shallow central depression. The lateral antennae emerge from a pair of minute tubules in the usual position. The mastax is of the modified malleate type. The rami triangular and carry a pair of minute denticulate combs just inside the types, one on each ramus. The unci each have five unequal, opposing, club-shaped, functional teeth with two or three accessories attached to the dorsal teeth near their bases. The remainder of the anatomy is normal. The lateral view of this species is quite characteristic. The dorsal plate begins of fall away gradually towards the foot at a point over the constriction between the stomach and intestine, giving the animal a very shallow appearance at the posterior portion of the body. The very slender toes, together with the absence of a posterior notch are enough to separate it from the other species of the genus. (ref. ID; 3246)
Measurements
Length of dorsal plate 335; length of ventral plate 225; width of dorsal plate 180; width of ventral plate 130; length of toes 90 µm. (ref. ID; 3246)
Length of dorsal plate 250-280; width of dorsal plate 130-175; length of toes 68-100 µm. (ref. ID; 3275)
Body is ovoid and in cross section resembles arc of a circle or slightly triadiate. Dorsal plate rises from neck and falls abruptly near foot, with a deep inverted U-shaped posterior notch. The width of longitudinal sulci is wider than in any other species. Trophi with four club shaped teeth in each uncus. A shield like process present covering the first foot joint. Toes long, slender, nearly straight and with a slight swelling near the tips. (ref. ID; 1934)
The lateral sulci are very deep in most specimens which are longer and wider than those described by Myers. (ref. ID; 2280)
Two variations were found: in some specimens the distyl ends of the toes were rapidly contracted to almost form a claw; in a few cases the shield over the foot was thickened dorsally. (ref. ID; 3127)
The body is roughly ovoid in dorsal view and a cross-section may resemble the arc of a circle or be roughly triradiate. The dorsal plate rises from the neck region to a point above the lateral antennae relatively higher than in any of the other species of Euchlanis, from where it falls away abruptly to the foot. The posterior notch is very deep and resembles an elongate, inverted U. The ventral plate is roughly about two-fifths of the dorsal in width and, as in the other species of Euchlanis, is connected to the dorsal plate by this cuticle forming longitudinal sulci. It is true that the width of the lateral sulci in Euchlanis is variable, depending on the state of nourishment and the development of the ova. However, in this species the dorso-ventral width of the lateral sulci is relatively uniformly wider than in any other species of the genus. Under the posterior portion of the dorsal plate and above the first foot-joint is a cuticular, shield-like process evidently protecting the delicate foot. The same structure is to be found in Euchlanis proxima and Tripleuchlanis plicata. The foot is two-jointed and very slender, with two pairs of very long setae projecting from dorsal side of the first-joint. The toes are very long, slender and nearly straight, with a slight swelling near the tips; their length is nearly one-half the length of the dorsal plate. The dorsal antenna is normal; the lateral antennae are in the usual position. The remainder of the anatomy is normal. The mastax is of the modified malleate type. The trophi have four strong clubbed, functional teeth in each uncus and there appear to be no the inside of the tip of each ramus are present. (ref. ID; 3246)
Comments
Lucks describes and figures this species, calling it Euchlanis oropha Gosse. Its closet relative is Euchlanis proxima, from which it differs in the smaller size, shape of the dorsal plate in lateral view, and the length and shape of the toes. (ref. ID; 3246)
Type locality
Euchlanis meneta is common in bodies of permanent water in Atlantic country, New Jersey; Mt. Desert Island, Maine and Vilas County, Wisconsin. (ref. ID; 3246)
Measurements
Length of dorsal plate 160, width 140; length of ventral plate 140, width 100; toes 70 µm. (ref. ID; 2280)
Length of dorsal plate 120-140; length of ventral plate 100-120; length of toes 65-75; width of dorsal plate 80-100; width of ventral plate 50-65; depth of posterior notch 35-45 µm. In young individuals the toes are frequently equal to the remainder of the body in length. (ref. ID; 3246)
Lorica length 110; lorica width 93; toe 54 µm. (ref. ID; 4606)
Body is ovate, truncate in front, rounded behind and in cross section resembles arc of a circle. Dorsal plate with deep posterior inverted U-shaped notch. Ventral plate nearly of the same length as the dorsal with longitudinal sulci. Foot stout and two-jointed. Toes broad and stout gradually increasing in width and falling to points. Mastax with 4 opposing club shaped teeth in each uncus. Rare in occurrence. (ref. ID; 1934)
Body oval. Dorsal plate has a deep notch at the posterior end. Toes wide. The anterior end is more or less straight and characteristic. (ref. ID; 2715)
The body is ovate in shape, truncate in front, rounded behind, and a cross-section resembles the arc of a circle. The dorsal plate has a deep posterior notch shaped like and inverted U. The ventral plate is nearly as large as the dorsal all around; it is joined to the dorsal plate by a pair of longitudinal sulci extending the entire length of the body. The foot is stout and two-jointed. The presence of foot-setae was not determined, owing to the small amount of material available. The toes are short and stout, gradually increasing in width for about two-thirds their length then falling away to acute points; they are about one-fourth the length of the dorsal plate. The dorsal antenna is normal to the genus and the lateral antennae are in the usual position. The mastax is modified malleate in type. There are four, opposed, clubshaped, functional teeth in each uncus and the usual pair of denticulate, fan-shaped, comb-like processes are present, one on the inside of each ramus tip. The retrocerebral sac, eye and remaining anatomy are normal. (ref. ID; 3246)
Comments
E. oropha is closely related to E. dilatata but differs in the structure of the foot and more robust toes, increasing in width for about two-thirds of their length and falling away in shape. (ref. ID; 1929)
Euchlanis oropha is closely related to Euchlanis dilatata from which it differs mainly in the stouter foot and more robust differently shaped toes. The tooth formula is the same in the two species, with minor differences in the accessory teeth which are probably subject to variation. (ref. ID; 3246)
Measurements
Length of dorsal plate 252; width of dorsal plate 182; length of ventral plate 224; width of ventral plate 154; length of toes 84 µm. (ref. ID; 1934)
Length of lorica 190 µm. (ref. ID; 2715)
Length of dorsal plate 210; width of dorsal plate 140; length of ventral plate 174; width of ventral plate 120; length of toes 65; width of toes 10 µm. (ref. ID; 2825)
Length of the dorsal plate 200; length of ventral plate 180; width of dorsal plate 130; width of ventral plate 115; length of toes 70 µm. (ref. ID; 3246)
Lorica length 225; lorica width 162; toe 68 µm. (ref. ID; 4606)
E. parva resembles E. dilatata but differs by its small size and long slender toes. Rousselet (1892) considered the large lateral antenna as a distinctive character. But Myers (1930) claimed, that because of the smaller size of the animal the antenna might have appeared relatively large. (ref. ID; 1934)
Rousselet says that one of the distinguishing characters of Euchlanis parva is the large size of the lateral antennae. His specimens must have been small ones as the lateral antennae do not vary much in size with the size of the individual. A small specimen would naturally appear to have larger lateral antennae than a larger one. In fact, the tubular lateral antennae are very uniform in size throughout the genus Euchlanis. Euchlanis parva resembles Euchlanis dilatata but is readily distinguished from it by its smaller size and by the very long, slender toes. It is a cosmopolitan species, being found everywhere in the littoral region of permanent bodies of water among aquatic vegetation. (ref. ID; 3246)
Descriptions
Body is ovoid and high arc of a circle in cross section. Dorsal plate with a deep inverted U-shaped notch posteriorly. Ventral plate nearly of the same size with longitudinal sulci. Toes long, slender, gradually increasing in width and falling rapidly to points. Mastax with 4 club shaped teeth in each uncus. (ref. ID; 1934)
The ventral plate is the arc of a low circle. There was some variation between specimens in the width/length ratio of the dorsal plate, which was from 0.76-0.96. (ref. ID; 2282)
The body is ovoid in shape, truncate in front, round behind. A cross-section resembles the high arc of a circle. The dorsal plate is medially divided posteriorly by a deep U-shaped notch. The ventral plate is nearly as large as the dorsal all around and is connected to the dorsal plate by two lateral, longitudinal sulci, one on each side. The usual pair of long setae project from the dorsal side of the first foot joint. The toes are long and slender, gradually increasing in width from the bases to near the tips, from where they fall away rapidly to acute points: their length is more than one-third that of the dorsal plate. The dorsal and lateral antennae are normal and in the usual positions. The mastax is of the modified malleate type. These are four opposed, club-shaped, functional teeth in each uncus with several, accessories attached to the dorsal teeth near their bases. The rami have a pair of minute fan-shaped, denticulate combs, on one the inner side of each tip. The retorocerebral sac, eye-spot, and remaining anatomy are normal to the genus. (ref. ID; 3246)
Measurements
Length of dorsal plate 144; width of dorsal plate 112; length of ventral plate 126; width of ventral plate 84; length of toes 56 µm. (ref. ID; 1934)
Length of dorsal plate 125; width of dorsal plate 120; length of ventral plate 115; width of ventral plate 80; length of toes 80 µm. (ref. ID; 2282)
Length of dorsal plate 140; width of dorsal plate 98; length of ventral plate 128; width of ventral plate 86; length of toes 50; width of toes 5-6 µm. (ref. ID; 2825)
Length of dorsal plate 140; width of dorsal plate 100; length of ventral plate 125; width of ventral plate 75; length of toes 70; depth of posterior notch 50 µm. (ref. ID; 3246)
Length of dorsal plate 200-235; width of dorsal plate 120-145; length of toes 80-92 µm. (ref. ID; 3275)
The body is orbicular in dorsal view and triradiate in cross-section. The dorsal plate is produced laterally into wide flanges, and has a high median keel extending its entire length. The venter is joined directly to the lateral edges of the dorsal plate without the intervention of longitudinal sulci. There is no posterior notch. The foot is obscurely two-jointed; two long setae project from the dorsal side of the first foot joint. The toes are long, slender and nearly straight, slightly enlarged posteriorly and end in rather abrupt points. The dorsal antenna is large in diameter and obliquely truncate; it bears a small tuft of sensory setae in a shallow, central depression. The lateral antennae are minute tubules in the usual position. The mastax is of the modified malleate type. There are five opposing, clubshaped, functional teeth in each uncus, with several minute accessory teeth attached to each of the dorsal teeth. The rami are triangular and the tips are abruptly reduced to acute points, on the inside of each is a finely denticulate, fan-shaped comb-like process. (ref. ID; 3246)
Comments
This species bears a superficial resemblance to Euchlanis triquetra, from which it differs in its greater size; the absence of a ventral plate and posterior notch. (ref. ID; 3246)
Measurements
Length of dorsal plate 300-500; width of dorsal plate 270-450; length of toes 90-150 µm. (ref. ID; 3246)
Euchlanis phyrne Myers, 1930 (ref. ID; 1345, 3246 original paper)
Descriptions
The general shape of the body is oval. The lateral edges of the dorsal plate are pinched in near the middle part and there is a deep, inverted U-shaped posterior notch, which is nearly as deep as the toes are long. The ventral plate is stiffened throughout, and longitudinal sulci connect it with the dorsal plate. The foot is two-jointed and has the usual pair of long setae projecting from the first foot joint. The toes are short, fusiform, slightly swollen in the middle portion then gradually diminishing to the tips; their length is a little over one-fourth that of the dorsal plate. The dorsal antenna is normal and bears the usual tuft of sensory setae in a central depression. The lateral antennae are in the usual position. The trophi have four opposed, club-shaped, functional teeth in each ramus, and there are a pair of fan-shaped, denticulate combs, one on the inner side of the tip of each ramus. The foot glands are long and moderately stout. The remainder of the anatomy is normal. (ref. ID; 3246)
Comments
The dorsal plate bears a superficial resemblance to Dapidia pyriformis and one of the forms of Dapidia calpidia. The species differs from them by having a true ventral plate; a deep U-shaped posterior notch and different type of trophi. (ref. ID; 3246)
Type locality
Euchlanis phryne is rare, only a few individuals having been collected in Eagle Lake and Toad Hale, Mt. Desert Island, Maine. (ref. ID; 3246)
Measurements
Length of the dorsal plate 225; length of ventral plate 210; width of dorsal plate 180; width of ventral plate 150; length of toes 65 µm. (ref. ID; 3246)
Dorsally the shape of the soft lorica is a long ellipsoid, truncated concavely at the anterior end and showing a deep sinus posteriorly. From the ventral side the frontal corners of the dorsal plate seems to be folded over, forming a very large and wide head opening, as also shown in the lateral view. A separate round ventral plate covers the first foot-joint. The toes are long, slightly curved ventrally and have a blunt point. The unci of the malleate trophi have four teeth, the first one strongly broadened, the second one somewhat broadened. The fulcrum is wide, bent and scalloped laterally. The cross-section is high, rounded, but there is no keel. (ref. ID; 1499)
The body is ovoid in shape. The dorsal plate is evenly arched in lateral view and has a deep U-shaped posterior notch. The ventral plate is almost as large as the dorsal all around. Longitudinal sulci of flexible cuticle join the dorsal and ventral plates. Just under the posterior notch of the dorsal plate and above the first foot-joint is a cuticular, shield-like process that evidently protects the delicate foot. The foot is two-jointed and the pair of setae that usually project from the dorsal side of the first foot joint are wanting in this species. The toes are stout and blade-shaped; their length is about one-third that of the dorsal plate. The dorsal antenna is normal and the lateral antennae are in the usual position. The mastax is of the modified malleate type. The trophi have four clubshaped, functional teeth in each uncus and there are a pair of denticulate, fan-shaped combs, one on the inner side of the tip of each ramus. The remainder of the anatomy is normal. (ref. ID; 3246)
Comments
This species is closely related to Euchlanis meneta. While the trophi are very similar and both have a protective, shield-like process above the first foot-jointed, the toes of Euchlanis proxima are relatively much shorter and stouter than those of Euchlanis meneta; the lateral view of the lorica of Euchlanis proxima is evenly arched, while the lateral view of Euchlanis meneta is very high in the lumbar region and falls away abruptly to the foot. The dorsal plate of E. proxima is constant, being evenly arched in cross-section, while the dorsal plate of E. meneta is variable and may be evenly arched or triradiate, and indicated by the dotted line. (ref. ID; 3246)
Type locality
Euchlanis proxima is rare. It was collected in submerged sphagnum near the bank of an acid brook about three miles south of Tuckertown, New Jersey (pH 6.0). (ref. ID; 3246)
Measurements
Body length 110-154; body width 70-85; height 60-70, toes 50-57 µm. (ref. ID; 1499)
Length of the dorsal plate 105; length of ventral plate 90; width of dorsal plate 105; width of ventral plate 90; length of toes 50 µm. (ref. ID; 3246)
All the specimens examined were very large and with the posterior edge of the plate slightly emarginated. The salivary glands were prominent. (ref. ID; 2283)
The body is orbicular in shape, truncate in front, round behind. The lateral edges of the dorsal plate are often pinched in near the middle. The venter is membranous, only the posterior portion being stiffened; there are no lateral sulci. The foot is obscurely two-jointed and ahs two pairs of long setae projecting from the dorsal side of the first foot joint. The toes are short, stout and nearly parallel sided; their length in little over one-fourth that of the dorsal plate. The dorsal and lateral antennae are normal and in the usual positions. There are a pair of prominent dorsal salivary glands attached to the mastax, one on each side of the opening of the oesophagus. The gastric and foot glands are stout and large. The remaining anatomy is normal. (ref. ID; 3246)
Comments
It has much in common with Dapidia calpidia and Dapidia deflexa. In these three species, the type of the mastax is the same, the rami differing from Euchlanis as pointed out previously; they all have membranous venters without lateral flanges or longitudinal sulci, in place of the ventral plates as found in the genus Euchlanis; they all have prominent dorsal salivary glands arising from anterior portion of the mastax. Neither Dapidia deflexa nor pyriformis has true posterior notches, but may have slight emarginations instead, depending on the state of contraction of the individual. The lorica of Dapidia pyriformis is constant, so far as is known, with the middle portion of the dorsal plate always pinched in. The lorica of Dapidia calpidia, its nearest relative, is variable in depth and the lateral edges of the dorsal plate may, or may not, be pinched in. (ref. ID; 3246)
Measurements
Total length of body 380-410; length of toes 110-130 µm. (ref. ID; 2283)
In specimens from Epping Forest, England; length of dorsal plate 285; width of dorsal plate 275; length of toes 80 µm. In specimens from Karlsruhe, Baden; length of the dorsal plate 320; width of dorsal plate 315; length of toes 85 µm. (ref. ID; 3246)
Length of dorsal plate 263; width of dorsal plate 235; length of toes 55 to 65 µm. (ref. ID; 3275)
Euchlanis semicarinata n. sp. can be distinguished from its keel-bearing congeners E. incisa Carlin and E. triquetra Ehrenberg by the incomplete keel. It moreover differs from the latter species in having a well-developed ventral lorica. Minute combs on the tips of the rami, reported present in both E. incisa and E. triquetra were not observed in the present species. E. semicarinata n. sp. lacks the pair of antero-dorsal ridges on the dorsal lorica which characterise the insufficiently described E. mamorokaensis Berzins. (ref. ID; 2844)
Descriptions
Lorica relatively soft, with arched dorsal and flat ventral plate, separated by lateral sulci. Dorsal lorica ovoid, anteriorly truncate. Mediodorsal keel present in posterior part of lorica, always preceded by smooth region. Shallow posterior notch present. Lateral antennae present postero-laterally. Ventral lorica ovoid, convex anteriorly. Foot two-joined, toes long, slender, parallel-sided, with or without distinct tips. Trophus: Manubria proximally broad, with straight cauda, unci with 5-6, partially connected teeth, rudimentary anterior and posterior tooth present. Rami tips smooth. (ref. ID; 2844)
Male: Male unknown. (ref. ID; 2844)
Etymology
The name Euchlanis semicarinata is derived from the Latin semicarinatus, referring to the incomplete dorsal keel of the species. (ref. ID; 2844)
The contents of the stomach were usually green, indicating a diet of live algae. The mastax was often of a beautiful red colour. The animals varied considerably in size. (ref. ID; 1450)
Body ovoid. Dorsal plate triradiate in cross section, with a median keel from neck to the anterior angle of posterior inverted V-shaped notch. Ventral plate with longitudinal sulci. Foot two-jointed. Toes slender, fusiform. Mastax with five club shaped opposing teeth in each uncus. (ref. ID; 1934)
The dorsal plate is large than the ventral plate, is triradiate in cross section, and has a median keel. The sides are roundly expanded; in lateral view the highest portion is at the center, gradually decreasing in height anteriorly and decreasing suddenly near the posterior end. The ventral plate is slightly concave, about two thirds as wide as the dorsal plate. (ref. ID; 3063)
The body is ovoid in shape, truncate in front, rounded behind. The dorsal plate is triradiate in cross-section and has a high median keel extending from the neck region to the anterior angle of the posterior notch. The posterior notch is triangular and shaped like an inverted V. The ventral plate is about three-fifths the width of the dorsal. Longitudinal sulci of flexible cuticle unite both plates laterally. The foot is two-pointed and a pair of long setae project from the dorsal side of the first foot joint. The toes are slender, fusiform and about one-third the length of the dorsal plate. The dorsal antenna is normal and the laterals are in the usual position. The trophi have five functional, club-shaped teeth in each uncus and there are the usual pair of denticulate combs, one on the inner side of the tip of each ramus. The remaining anatomy is normal to the genus. (ref. ID; 3246)
Comments
E. triquetra resembles E. pellucida but differs in its smaller size and with a ventral plate with sulci. (ref. ID; 1934)
Euchlanis triquetra resembles Euchlanis pellucida superficially, but is consistently smaller and readily distinguished from the latter by the presence of a ventral plate. The smaller species bear a certain resemblance to the triradiate form of Euchalnis dilatata. The differences are discussed in the course of the description of Euchlanis dilatata. (ref. ID; 3246)
Measurements
Length of dorsal plate 280; width of dorsal plate 210; length of ventral plate 204; width of ventral plate 154; length of toes 84 µm. (ref. ID; 1934)
Length of dorsal shell 250-710; breadth of shell 200-504; height of shell -300; toe length -150; trophi length -40 µm. (ref. ID; 2834)
Length 220, width 240 µm. (ref. ID; 3063)
Euchlanis triquetra varies considerably in size depending on food conditions and the environment. Length of the dorsal plate 210-270; length of ventral plate 180-240; width of dorsal plate 155-240; width of ventral plate 105-160; length of toes 70-85; depth of lorica 140-180 µm. (ref. ID; 3246)
Two quite distinct species have been described under this name. Ehrenberg's species has no lateral sulci, the edges of the ventral plate of the lorica being fused with those of the dorsal plates except at the head and foot openings. The form described at a later date by Hudson & Gosse (1886) under this name has a separate ventral plate with free lateral edges and has be renamed E. incisa by Carlin (1939). (ref. ID; 3208)
Euchlanis triquetra var. nhamundaiensis Brandorff, Koste & Smirnov, 1982 (ref. ID; 2834 original paper)
Descriptions
These animals are very transparent. The surface of the shell is delicately pitted and its outline is broad elliptical. The central carina surpasses the caudal part of the dorsal shell. While E. triquetra triquetra has a reverse T-shaped cross-section with a high carina and wing-like lateral processes, the nov. var. has a low and short dorsal carina and short wing-like lateral prominences. A ventral plate can be seen near the indentation of the head. Otherwise the ventral plate is replaced by a thin membrane. The symmetrical jaws are not different from the forma typica. Possibly the wavy margins of the lateral prominences and of the dorsal carina are generated by fixation. In the stomach we found capsules of diatoms. (ref. ID; 2834)
Measurements
Length of dorsal shell 250-518; breadth of shell 240-420; height of shell 240-415; toe length 90-120; trophi length -40 µm. (ref. ID; 2834)
