Worm Breeder's Gazette 3(2): 22
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
The development of the male has been followed to maturity, and the fates of the cells produced by the post-embryonic lineages are now known. Here are a few of the novel points. 1. Sensory rays. The nine pairs of sensory rays are composed of three cells: two neurons and a sheath cell. These sensilla are the only structures in the tail for which there is a clear repeating pattern of cell assignments. 2. Formation of the cloaca and spicules. Daughters of the B cell make up the spicules, each composed of 2 neurons, 4 socket cells and 2 sheath cells. Other cells form the spicule channels and a neuron with striated rootlet that lies over the base of the spicule and probably is a proprioceptor. The elongated shape of the spicules and cloaca is obtained by the dorsal spicule retractor muscles which attach to the dorsal edge of the cloaca and crawl anteriorly. In their absence the cloaca is short and the spicules are crumpled. 3. Rearrangement of the anal depressor muscle. During L4 lethargus, the myofilaments of the depressor muscle detach dorsally and rotate through 90 before reattaching to the gubernaculum. The function of the muscle is thereby completely altered. In the absence of post-embryonic muscle the rearrangement is incomplete: some filaments run in each direction. 4. Regulation. Cell ablations (by laser microbeam) in the young L1 have revealed some capacity for regulation in two areas. (a) Rays are ordinarily made by V5(one), V6(five) and T (three). After ablation of V6, V5 can make most of the rays normally produced by V6. After ablation of V5 and V6, V4 can make one or two rays. Other V cells have not been seen to produce rays, perhaps because they arrive at the tail too late, but V3 was stimulated to go through an extra round of division. (b) Extra neurons, supporting cells and hypodermal cells are added to the preanal ganglion, normally by division of P10.p and P11.p. After ablation of P10.p or P11.p, P9.p can be recruited to this function; the resulting animal is perfect except for the trivial loss of a ventral hypodermal nucleus. No other cell has ever been recruited.