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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 3065

Sudzuki Minoru; [On the General Structure and the Seasonal Occurrence of the Males in Some Japanese Rotifers. II.]. Zoological Magazine (Dobutsugaku Zasshi) 64(3):130-136, 1955

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This paper deals with the general structure and the seasonal occurrence of the males in some Rotifer (2 genera, 7 species) occurring in the same habitats mentioned in my previous paper. 3). Brachionus angularis Gosse: The species was perennial, and di- or polycyclic in R1 and mono- to dicyclic in M1. Total length is 88-92 µm, body length 65-75 µm, width 46 µm. 4). B. calyciflorus Pallas: This species was perennial, and dicyclic a both places. Total length 107-135; body: 78-108 in length, 51-76 µm in width and 44 µm in height. 5). B. forficula Wierzejski: Such forms are volgensis, typica, divergens, voronkowi and minor etc. were found together with various intermediate types. D-Female appeared soon after the occurrence of Male-Female in July, and the sexual phase was found till the end of September. Therefore, the present species seems to be a monocyclic summer form. The mictic females and three kinds of eggs are illustrated besides the males. Total length is 77-96 µm, body length 59-69 µm, width 37-39 µm, height 37-38 µm. 6). B. budapestinensis Daday: All individuals observed belonged of f. lineatus (Skorikov). This species seems to be perennial. The mictic females occurred in spring and fall as in B. calyciflorus but copulating ones were rarely recognized also in summer. The Male-Female female and three kinds of eggs are figured. 7). Keratella quadrata (Muller); This species from my places was identical with K. quadrata quadrata and may be perennial (sporadical in summer). The mictic females appeared from the end of March to the beginning of May in 1953, but in 1954 no sexual period was observed in spring. 80-90 µm long by 40-45 µm broad. 8). K. valga (Ehrenberg): Under the valga-group, such forms as tropica, asymmetrica, monstrosa were found. The species was perennial, and monocyclic in R1 but dicyclic M1. Male-Female, D-Female belonged mainly to monstrosa, but often to asymmetrica, total length 91 µm, body length 75 µm, width 38 µm. 9). K. stipitata (Ehrenberg): This species belonged to typica or robusta and perennial. The sexual period was observed during a month following the middle of October, but in 1952 two specimens of Male-Female were collected in July 7. The sexual females were generally represented by reduced non-spined forms, but were rarely found among spined forms, typica-micracantha. Total length 77 µm, body length 55-65 µm, width 35 µm, height 35-42 µm.