QO NORTH AMERICAN 



PLATE IV. ' 

 TERATOCEPHALUS, de Man, 1876. 



Fig. 8. Tcratocephalus cornutus, n. sp. I, lateral view of a female; II, 

 lateral view of head, more highly magnified; III, front view of head; IV, 

 dorso-ventral view showing lips wide open; V, cuticle showing lateral field. 



a, one of the six movable, chitinous lips ; b, one of the four submedian 

 cephalic setae ; c, amphid ; A, nerve-ring ; e, excretory pore ; f, organ of un- 

 known significance ; g, cardiac bulb ; h, intestine ; i, anus ; /, rectum ; k, cu- 

 ticle ; /, one of the cells of the intestine; m, lumen of the intestine; nn, flex- 

 ures in ovary ; o, egg ; p, vulva ; q, blind end of posterior ovary ; u, terminus. 



ALAIMUS, de Man, 1880. 



Fig. 9. Alaimus simplex, n. sp. I, lateral view of a female; II, an- 

 terior extremity, lateral view; III, posterior extremity of a male, lateral view. 



a, lip region ; b, pharynx ; c, amphid ; d, amphid, enlarged; e, group of 

 spermatozoa at the posterior portion of the ovary; f, blind end of ovary; 

 g, male supplementary papillae ; //, left spiculum ; i, terminus ; j, rudimentary 

 submedian elevation or flap of the cuticle, indicating rudimentary bursa; k, 

 egg ; I, vulva ; m, nerve-ring ; n, posterior extremity of oesophagus ; p, modi- 

 fied cells of anterior portion of the intestine ; q, cuticle ; r, wall of the in- 

 testine ; s, lumen of the intestine ; t, flexure in the single ovary. 



The arrangement of the ova and eggs may need a few words of ex- 

 planation. The rounded blind end of the reflexed part of the single ovary 

 is shown near the group of spermatozoa, e. The blind end contains a large 

 number of oocytes of small size. These oocytes have more than doubled 

 in size by J;he time they have reached the position, /. Henceforth they be- 

 come arranged single file, always increasing in size until they pass the 

 flexure, t. "At k a deceptive appearance is shown, inasmuch as the ripe 

 ovum, k, has passed the flexure and in its passage to the uterus is pressing 

 two of the unripe ova apart. This accounts for the apparent anomaly in 

 relative size of the^ova in the vicinity of the flexure. 



PLECTUS, Bastian, 1865. 

 Fig. 10. Plectus tubifer, n. sp. Male specimen, lateral view. 



a, lips ; b, papilla-like cephalic seta ; c, amphid ; d, anterior chamber of 

 pharynx ; e, posterior chamber of pharynx ; /, lumen of the oesophagus ; g, 

 nerve-ring ; h, excretory pore ; i, renette cell ; /, cardiac bulb ; k, vulva of 

 cardiac bulb ; /, cardia ; m, lumen of intestine ; n, blind end of anterior testis ; 

 o, spermatocyte ; p, junction of testes; q, blind end of posterior testis; r, be- 

 ginning of vas, deferens; s, spermatozoon; t, male glands; u, one of the cau- 

 dal glands; v, anterior of the three tubular supplementary organs; w, spicula; 

 x, anus; y, one of the nine male papillae; z, spinneret. 



