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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Bdellodrilus

Bdellodrilus Moore, 1895 (ref. ID; 1923)

Superclass Clitellata: Class Branchiobdellida: Family Bdellodrilidae (ref. ID; 6456)

ref. ID; 1923

Without setae; with posterior sucker; pharynx with dorsal and ventral chitinous jaws; commensal on crayfish. With two pairs of testes in segments 5 and 6. Body with appendages. Accessory sperm tube absent. With a pair of large clear glands in each of the 9 postcephalic segments; spermatheca bifid. Single species. (ref. ID; 1923)
  1. Bdellodrilus illuminatus (Moore, 1893) (ref. ID; 6651) or (Moore, 1894) (ref. ID; 1923) reported author and year? (ref. ID; 6456)

Bdellodrilus illuminatus (Moore, 1893) (ref. ID; 6651) or (Moore, 1894) (ref. ID; 1923) reported author and year? (ref. ID; 6456)

Descriptions

The spermatozoon of this species is characterized by a short conical "acrosome" filled with homogeneous electron-dense material and surrounded by the plasma membrane. Occasionally the apex of the acrosome is characteristically bent to one side. In the absence of any ultrastructural evidence, it is called the acrosome only because of its position anterior to the nucleus. The nucleus is anteriorly rectilinear for about 4 um and then slightly helical for the rest of its length. No concavity is visible at the anterior end of the nucleus, but one is present at the posterior end. Four mitochondria are tightly packed together and slightly twisted about the longitudinal axis of the spermatozoon. The tail consists of a long flagellum and an unusual end-piece. The flagellum starts with a deeply modified "centriolar area", represented by a highly electron-dense, hollow cylinder with a diameter and length of 0.25 um. In the walls of this cylinder are nine electron-lucent spots arranged in the same position as the triplets. The structure is derived from a conventional centriole and becomes modified in the course of spermiogenesis (M. Ferraguti, unpublished observation). Inside this centriolar remnant a central structure is present, similar to the one described in other clitellates. This structure continues along the flagellum, forming a prominent central sheath, and glycogen granules are present in their usual position. The twisted end-piece is a triangular prism, with each surface approximately 0.16 um wide and 110 um long, and with a pitch of about 1.7 um. Electron-dense material is arranged in a thick rod down the center and three thin rods lying along each edge of the prism. (ref. ID; 6456)