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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Helodrilus

Helodrilus Hoffmeister, 1845 (ref. ID; 1257)

Family Lumbricidae (ref. ID; 1928, 6618)

Family Lumbricidae: Subfamily Lumbricinae Michaelsen, 1910 emm. Omodeo, 1956 (ref. ID; 1257)
  1. Helodrilus (Bimastus) beddardi (Mchsln.) (ref. ID; 1928)
  2. Helodrilus (Allolobophora) caliginosus typica (Sav.) (ref. ID; 1928)
  3. Helodrilus (Allolobophora) caliginosus var. trapezoides (Ant. Duges) (ref. ID; 1928)
  4. Helodrilus (Allolobophora) chloroticus (Sav.) (ref. ID; 1928)
  5. Helodrilus (Bimastus) constrictus (Rosa) (ref. ID; 1928)
  6. Helodrilus (Bimastus) eiseni (Levinsen) (ref. ID; 1928)
  7. Helodrilus (Eophila) ictericus (Sav.) (ref. ID; 1928)
  8. Helodrilus (Allolobophora) longus (Ude) (ref. ID; 1928)
  9. Helodrilus (Dendrobaena) mammalis (Sav.) (ref. ID; 1928)
  10. Helodrilus (Eophila) oculatus Hoffmeister, 1845 (ref. ID; 1257, 1928)
  11. Helodrilus (Dendrobaena) octaedrus (Sav.) (ref. ID; 1928)
  12. Helodrilus patriarchalis (Rosa, 1893) (ref. ID; 6618)
  13. ?Helodrilus (Allolobophora?) relictus Southern, 1909 (ref. ID; 1928 original paper)
  14. Helodrilus ribaucourti Cognetti, 1901
    See; Dendrobaena cognettii gallurensis Rota, 1992 (ref. ID; 6038)
  15. Helodrilus (Dendrobaena) rubidus typica (Sav.) (ref. ID; 1928)
  16. Helodrilus (Dendrobaena) rubidus var. subrubicunda (Eisen) (ref. ID; 1928)

Helodrilus (Allolobophora) caliginosus typica (Sav.) (ref. ID; 1928)

Descriptions

In 1894 Friend (tom. cit.) referred some worms from Co. Clare to the species Allolobophora georgii, Mchlsn., which had not previously been recorded from the British Isles. This species is confined to the Mediterranean region. Three of the specimens so named by Friend are in the National Museum, Dublin. On examination they turned out to be undoubted specimens of Helodrilus caliginosus, one of the commonest Irish earthworms. Southern had specimens H. georgii from Sardinia for comparison. It thus seems probable that Friend was mistaken in his identification, and H. georgii must be struck off the British List. (ref. ID; 1928)

Helodrilus (Allolobophora) caliginosus var. trapezoides (Ant. Duges) (ref. ID; 1928)

Descriptions

Transition forms of all stages are extremely common between this variety and the type form. It is probable that the differences in the tubercula, by which the two forms are separated, either represent different stages of development or that the character is very variable. (ref. ID; 1928)

Helodrilus (Dendrobaena) octaedrus (Sav.) (ref. ID; 1928)

Descriptions

A well-marked variety occurs, distinguished by very prominent glands at the male pores. There are also papillae on the 16th segment, and the segments are more clearly defined than in the typical form. One specimen from Co. Kerry was 70 mm long, the usual length being 25-40 mm. The clitellum in all specimens stretched over segments 29-33, without exception. (ref. ID; 1928)

?Helodrilus (Allolobophora?) relictus Southern, 1909 (ref. ID; 1928 original paper)

Descriptions

This species, of which only a single specimen was obtained from Clare Island, off the west coast of Ireland, is so remarkable in structure that Southern hesitated for some time whether to describe it as a new species or to regard it as a monstrosity. These is no doubt that the specimen is an abnormal one. This is clearly shown by the spiral arrangement of some of the segments, which are divided and contain two sets of setae on one side, whilst they are single and with only one set of setae on the other. The male reproductive organs also are quite unique amongst the Lumbricidae; and the whole structure differs widely from that of any other British type. It is not justifiable, however, to regard all its specific differences as being due to individual mutation, since it approaches in structure two species, H. (A.) molleri, and H. (A.) mobii, the former occurring in Portugal, the latter in Medeira, the Canaries, and Tangiers. Taking into account its relation to these two western species, and its occurrence on an isolated island off the west of Ireland, one is tempted for the present to regard it as a surviving member of a very old species. It is probable that more material will shortly be obtained from Clare Island, and new light may be thrown on this isolated form. Length 40 mm; width 2 mm; number of segments, 126. Dorsally the worm is dark purple, the anterior segments shining with a greenish-purple iridescence. The ventral surface is much paler. The prostomium cuts back to the second segment, as in the genus Lumbricus. So far as cloud be ascertained the first dorsal pore is between segments 11 and 12. The setae are closely paired; ab is slightly greater than cd; aa = 4 ab, bc = 3 ab. The setae ab are more prominent than cd all along the body. The spiral arrangement of the segments makes it difficult to setae the exact position of the various papillae, the clitellum, etc. The chief aberrations are:
  1. On the 15th segment there are two pairs of lateral setae on the right side.
  2. The 20th segment on the right side is double on the left.
  3. Segments 33 and 34 on the left side correspond to 4 segments, 32-25, on the right side.
  4. Segment 46 on the right side corresponds to 45 and 46 on the left side.
  5. Segment 53 on the right side corresponds to 53 and 54 on the left side.
  6. Segment 65 on the right side corresponds to 66 and 67 on the left side.
Prominent ventral papillae occur on segments 19 and 20 right side, 19 and 21 left side. There are also papillae on segments 50, 51, 59 right side, 50, 51, 60, and 62 left side. On the right side, the clitellum covers segments 50-59, and the tubercula stretch as an unbroken line over segments 51-58. On the left side the segment corresponding to 53 is divided, and the tuberculum is interrupted at this point. On segment 24 and 25 (right side) there are two pairs of small but distinct pores just above the ventral setae. The male pores open on segment 28, and are surrounded by very indistinct glandular prominences. Having only a single specimen to dissect, Southern was unable to determine the precise relations of the genital organs. This applies especially to the female organs. There are 4 pairs of spermathecae present in segments 17-20. The most astonishing fact was the presence of 3 pairs or testes and sperm-funnels in segments 18, 19, and 20. They are large, glistening, and much folded. There appeared to be 4 sperm-sacs in segments 17, 19, 20, and 21; but Southern was unable to determine their precise relations to each other, and the figure given is only approximate in this respect. The last pair of sperm-sacs was the largest, stretching through 2 segments. The female organs were not observed, but it seems likely that the small pores on segments 24 and 25 were the openings of the oviducts, in which case the female organs would also be abnormal in number and position. The presence of three pairs of testes and sperm-ducts is quite unique in the Lumbricidae, the usual number being two pairs. Several species have been described, however, such as Octolasium hemiandrum (Cognetti), Octolasium damianii Cognetti et al., which have only a single pair of testes. In Octolasium damianii, the opening of the male duct is on the 27th segment. Southern have provisionally placed this species in the sub-genus Allolobophora, as it has 4 pairs of sperm-sac. The backward position of the clitellum, which so markedly distinguishes it from other British species, points to relations with the two western species Helodrilus (A.) molleri (Rosa), and H. (A.) mobii (Michaelsen). Among the specific characters will probably be the position and extent of the clitellum, and the shape of the prostomium. (ref. ID; 1928)

Helodrilus (Dendrobaena) rubidus var. subrubicunda (Eisen) (ref. ID; 1928)

Descriptions

This is almost invariably found under the bark of fallen trees. (ref. ID; 1928)