56 



they measure about 0.2 mm. in thickness, the tail continuing 

 about a millimeter beyond, straight and almost effilate, to a 

 fine point. The tail of the male (Figs. 7 and 8) ends obliquely, 

 closely resembling the tail of Oxyuris megatyphlon in general 

 appearance, and presenting an ungulate tip as in the latter 

 worm; the tail of male examples widely curved to ventral 

 side. The worms are colorless, the cuticle transparent, 

 delicate, and finely striated transversely. The longitudinal 

 granular bands seen in 0. megatyphlon are absent. 



Mouth small, provided with three nearly equal lips (Fig. 3), 

 each with two fairly prominent papilhe; esophagus (Figs. 5 

 and 7) long and straight, without the fusiform widening 

 characteristic of 0. megatyphlon, and showing a well-marked 

 spheroidal ventricle (bulb) at the junction with the intestine 

 proper. Compared with O. megatyphlon (Fig. 12) it presents 

 a more slender esophagus; in fully developed females 

 occupying from one-sixth to one-third the body length (being 

 proportionately shorter and thicker in larger and gravid 

 specimens, in which it seems crowded anteriorly), and in 

 several males measured, nearly half of the full length. The 

 esophageal bulb, like that of 0. megatyphlon, contains a 

 three-pieced armament; and in large females is about 0.2 mm. 

 in diameter. The beginning of the intestine (the part called 

 the cecum by Rudolphi) is generally smaller than in 0. 

 megatyphlon, but rather variable; the intestinal tube straight. 

 In the female the anus is about a millimeter from the tip of the 

 tail (from 0.8 to 1.4 mm. in different examples measured), 

 and is guarded by two rather prominent transverse lips. 

 Just within, upon the walls of the intestine, are several small 

 rounded structures, probably anal glands. The anus of the 

 male opens subterminally in a cloaca with the genital organs. 

 Esophagus and intestine of both sexes brownish. The 

 calcareous granules seen so numerously upon the walls of the 

 intestine and generative tubes in 0. megatyphlon are absent. 



The generative apparatus (Fig. 5) of the female consists 

 of two ovarian tubes and their oviducts, closely plicated along 



