ART. 23 NEW NEMATODE WORMS CHANDLER 5 



the anterior end of the esophagus being attached to the side walls 

 of the vestibule. Vulva situated anteriorly behind the junction of 

 the esophagus and intestine. Ovejector long, with a bulblike en- 

 largement, with thick muscular walls at the vulvar end. Posteriorly 

 the vagina opens into a thin-Avalled tube filled Avilh embryos, whicli 

 extends jDOsteriorly a short distance and then splits into two uteri, 

 which continue posteriorly almost to the anus. Tail of female long, 

 rounded at the tip, Avithout any embellishments. Posterior end of 

 male coiled, with a long fingerlike tail, rounded at the tip, with a 

 number of pairs of inconspicuous postanal papillae and no proanal 

 papillae. Spicules very unequal, the longer one divided into a 

 troughlike anterior part and a more slender posterior part which 

 terminates in a filament. Shorter spicule troughlike, also with a 

 terminal filament. 



In many respects this genus is close to the genus Litomosa Yorke 

 and Maplestone, 1926, but differs in the character of the oral vesti- 

 bule and anterior end of the esophagus, in the position of the vulva, 

 in the absence of processes at the tip of the tail in both sexes, and 

 in the presence of postanal papillae. 



Type species. — Litomosoides sir/mod on tis, new species. 



LITOMOSOIDES SIGMODONTIS, new species 

 Figures 4, 5, 6, and 7 



/Specific diagnosis. — Litomosoides: Slender worms, cylindrical, 

 tapering to a bluntly rounded head anteriorly, and to a rather elon- 

 gate and slender conical tail posteriorly. Cuticle with very fine 

 striations except near the ends of the body. Head truncated in 

 dorsoventral view, unevenly rounded in lateral view, the mouth being 

 situated somewhat toward the ventral side. Oral vestibule 20fi to 23)w 

 long, with a narrow cylindrical lumen and heavily chitinized walls 

 which do not have straight parallel sides externally, but are drawn 

 out into points where the muscular fibers of the esophagus attach 

 to it. Esophagus muscular, not divided into separate parts, GOO/a to 

 G60|Li long, straight except for a bulbous enlargement anteriorly into 

 which the posterior half of the vestibule is sunk. Females over twice 

 as long as males. 



Male about 24 to 28 mm. long with a maximum diameter of about 

 IZOfi to 140,0,. Reproductive tube straight, without convolutions. 

 Cloacal aperture about ISO/a from tip of tail. Tail rounded at end. 

 tapering for about half its length behind the cloacal aperture, and 

 then almost cylindrical. No preanal papillae; four pairs of small 

 po:;tanal papillae, nearly equally spaced, the most distal one about 

 midway between cloaca and tip of tail; first pair of papillae, nearest 



