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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Magmatodrilus

Family Branchiobdellida (ref. ID; 6466)

Family Cambarincolidae (ref. ID; 6651)
  1. Magmatodrilus obscurus (G., 1940) (ref. ID; 6651) reported author and year? (ref. ID; 6466)

Magmatodrilus obscurus (G., 1940) (ref. ID; 6651) reported author and year? (ref. ID; 6466)

Descriptions

The acrosome is long. Although the acrosome tube is straight along the entire length, a few sperm have a slightly twisted anterior portion, the shape of the anterior end being similarly variable: straight, gently twisted, or bent to one side. The posterior end of the tube is more complex than usual, with the tube wall becoming thin and the bending inwards to form a limen. The acrosome vesicle protrudes beyond the anterior end of the tube and this too varies in form from a slight to a bulbous extension. Irrespective of the form, the plasm membrane supports a thin apical corona. The vesicle extends posteriorly to terminate just anterior of the limen in a thickened ring. The basal invagination passes through the vesicle's basal ring and extends into the anterior portion of the acrosome to form a large subacrosomal space filled with amorphous, quite electron-dense material. A short secondary rod is barely visible in the posterior acrosomal space just extending through the basal invagination. The nucleus is straight with an anterior conical concavity and a shallow posterior depression. The midpiece is long and penetrated only a little way by the central tubules of the axoneme. The flagellum has an axoneme with a prominent central sheath and a small helical marginal fiber coiled around the tail. (ref. ID; 6466)