86 NORTH AMERICAN 



EXPLANATION OF PLATES* 



PLATE II. 

 IOTA, Cobb, 1913. 



Fig i. Iota octangulare, n. sp. Lateral view of a female specimen. 

 a, lip region; b, labial chitinous plate or expansion; c, protruding muscles of 

 the spear ; d, spear ; e, trilobed base of the spear ; f, lumen of the oesophagus ; 

 g, nerve-ring; h, beginning of the intestine; i, flexure in the single narrow 

 ovary; j, excretory pore; k, ventral row of modified cuticular elements; /, 

 submedian row of modified cuticular elements; m, ovum; n, muscular layer; 

 o, anterior extremity of the uterus ; p, uterus ; q, cuticle ; r, vulva ; s, sub- 

 median row of modified cuticular elements ; t, rectum ; u, anus ; v, terminus. 



RHABDOLAIMUS, de Man, 1880. 



Fig. 2. Rhabdolaimus minor, n. sp. I, lateral view of female; II, head 

 of the same, showing amphid. The head in I is twisted, so that the amphid 

 appears as if ventral, or nearly so. 



a, amphid ; b, long, narrow pharynx ; c, anterior group of nerve cells ; d, 

 nerve-ring ; e, cardiac bulb ; /, wall of the intestine ; g, flexure in anterior 

 ovary; h, posterior group of nerve cells; i, body cavity; j, lumen of intestine; 

 k, ovum; I, blind end of posterior ovary; m, egg; n, flexure in posterior 

 ovary ; o, cuticle ; p, caudal glands ; q, subcuticle ; r, vulva ; s, rectum ; t, anus ; 

 u, nerve cells (?) ; v, duct of caudal glands; w, spinneret; x, lip region. 



DIPLOGASTER, Max Schultz, 1857. 



Fig. 3. Diplogaster fictor, Bastian. I, side view of female; II, head 

 of the same seen in dorso-ventral view, lips nearly closed ; III, head 

 of the same, lateral view, lips nearly wide open; IV, head of the same, 

 lateral view, lips partially closed; V, front view of mouth, partially closed; 

 VI, lateral view, posterior portion of a male specimen; VII, somewhat dia- 

 grammatic perspective view showing markings of the cuticle. 



a, one of the lips ; b, one of the six cephalic setae ; c, amphid ; d, one of 

 the two more or less evertible pharyngeal hook-shaped teeth; e, median 

 oesophageal bulb ; /, nerve-ring ; g, anus ; h, rectum ; i, intestine ; j, terminus ; 

 k, posterior oesophageal bulb; /, nerve cells; m, renette cell (?); n, left 

 spiculum; o, lumen of the intestine; p', preanal male seta; p" , P' ' ' , 

 p' ' ' ' , post-anal male setae and papillae; q, one of the cells of the intestine; 

 r, accessory piece ; s, flexure in anterior ovary ; t, blind end of anterior ovary ; 

 u, longitudinal striae of the cuticle ; v, vagina ; w, synapsis in egg in the an- 

 terior uterus, the reduced number of chromosomes being seven; x, one of the 

 spermatozoa in the ovary; y, uterus; z, vulva. 



*The drawings are used by permission of the Secretary of Agriculture, and were 

 made by Mr. W. E. Chambers, under the author's supervision. 



