EXPLANATION OF PLATES IX AND X. 



ClL^TOGASTER PEI^IyUCEDUS, n. Sp. 



Fig. I. — General view, seen (as are the others) by transparency. 



Fig. 2. — (See text-fig. 2, p. 238.) 



Figs. 3, 4, 5, 6, 7, — Semi-diagrammatic representations of succes- 

 sive stages in the growth of the animal. The Roman 

 numerals at the sides of the figures represent the num- 

 bering of the segments : it should be noted that the 

 first bundle of setae behind an}^ constriction becomes 

 the bundle of the sixth segment of the posterior animal. 

 Hence in these figures vi is placed opposite such setae, 

 although the anterior five segments of the animal may 

 not have yet grown so as to be recognisable. 



Fig. 8 a, h, c, d, e, /. — Successive stages of development of the 

 sperm-mornlse. 



Fig. 9. — Region of crop, showing genital organs : ventral view. 



Fig. 10. — The region of the male aperture : lateral view. 



An., anus; b.c, buccal cavity; b. co;izm., buccal nerve com- 

 missure ; b.g., buccal ganglion; e.g., cerebral ganglion ; con., con- 

 striction, which will ultimately divide the animal ; cr., crop ] cr ., 

 crop of second animal; d.v., dorsal blood-vessel; g.s., genital 

 setae; h., genital hairs; int., intestine; int., intestine of second 

 animal; l.n.c, lateral expansion of nerve-cord at sites of future 

 division ; m., mouth ; n., nephridium ; n. comm., the nerve com- 

 missures ; ce., oesophagus; ne ., oesophagus of second animal; 

 ov., ovary; r.s., receptaculum seminis; ph., pharynx ; ph ., pharynx 

 of second animal ; s ., first bundle of setse (of second segment) ; 

 s ., second bundle of setae (of sixth segment) ; s.m., sperm morulae ; 

 sp., septum ; s/)'., the first septum, i.e., septum | ; sp ., the second 

 septum, i.e., septum |; sph. g., subpharyngeal ganglion; st., 

 stomach; st ., stomach of second animal; sir., strands of tissue 

 between alimentary tract and body- wall ; s.s., small setae, visible 

 only with the high power at zones of budding; t., testis; i.n.c, 

 terminal expansion of nerve-cord ; v. comm. , vascular commissure 

 in head ; v.d., vas deferens ; y.w.c, ventral nerve-cord ; v. v., ven- 

 tral vessel ; cf , male aperture with genital setae. 



