90 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 50. 



Localities. — Germany (Saxony); Italy (Padua); Austria 

 (Trieste) ; United States (Washington, District of Columbia; Colo- 

 rado Springs, Colorado). 



The name Ascarls dlpodis Rudolphi, listed by Stossich as a syno- 

 nym of Oxyuris tetraj^tera, antedates the name proposed by Nitzsch, 

 but Eudolphi (1819) did not describe this species and lists it with a 

 cross, meaning " not seen." It can not therefore be considered as an 

 available name for this species. 



Molin's measurements indicate that the worm is one-fourth as 

 thick as it is long, an obvious error. He states that the spicule is 

 papilliform, a statement which is copied by Stossich. I have been 

 unable to identify any spicule in this species. 



This species has been very much confused wdth 0. oh^wlata^ but 

 the two are readily distinguishable. 



Spiroptera quadrialata (q. v.) is probably 0. tetraptera, 



OXYURIS TRIRADIATA Hall, 1916, new species. 



Specific diagnosis. — Oxyuris (p. G5) : Mouth with three promi- 

 nent outer lips (fig. 109), each bearing two papillae anteriorly, and 

 with three conical inner lips forming the triradiate mouth aperture 

 (fig. 110) common in species of Oxyuris. This communicates 

 through the simple pharynx with the club-shaped esophagus, which 

 becomes gradually thicker posteriorly and is separated b}^ a con- 

 striction from the powerful esophageal bulb. This bulb (fig. Ill) 

 is strongly muscled and the lumen is lined wdth chitin w^hich is de- 

 veloped into a dental apparatus in the posterior portion of the bulb. 

 The bulb communicates with the intestine by means of a valve which 

 projects into the lumen of the intestine. The anterior portion of the 

 intestine is dilated to form a wide elongate saccular structure, and the 

 posterior portion is constricted to form a narrower cylindrical 

 structure. There are no lateral alae, but the cuticle around the 

 head and neck, to a distance half the length of the esophagus, 

 is swollen, often forming incidentally a narrow ring just back 

 of the head. The cuticle is very distinctly transversely striate. 



Male 3.38 to 4.00 mm. long and 200 to 285 /x thick. The head 

 diameter is about 55 ii. The esophagus, exclusive of the bulb, is 310 

 to 345 /x long and 43 to 50 /x thick at the posterior end. The esopha- 

 geal bulb is 100 to 105 y, long and 95 to 105 /a thick. The nerve ring 

 is 200 to 260 )u back of the anterior extremity of the body. The 

 prominent cuticular striation disappears at the origin of the bursal 

 membrane anterior of the cloacal aperture (fig. 112) . The bursa forms 



