oxYURiDib;. 67 



solitary thread to the point of the tail. Notwithstanding the 

 minuteness of these details (as originally given by "Walter), the 

 somewhat more recent investigations of Schneider, Eberth, and 

 others, all tend to cast doubt on Walter's so-called nerve discoveries. 

 It is even said that Walter himself has admitted his descriptions to 

 be erroneous. 



The reproductive system follows without much deviation the 

 general Nematode type. The male apparatus, according to 

 Kuchenmeister, consists of a simple uniform tube or a seminife- 

 rous duct, in which neither testis nor vas deferens can be 

 clearly defined, the whole terminating in a grooved spiculum or 

 penis, which during exsertion passes out by the anal cleft. A small 

 accessory spicule, as in the genus Filaria, and a sucking disk 

 placed at the caudal extremity, assist ia fixing the parts during 

 sexual congress. In the female the apparatus consists of a narrow 

 oviduct or vagina, two broad uterine canals severally occupying 

 the upper and lower halves of the body, terminating in narrow 

 ovarian tubes with bhnd extremities. The vaginal outlet is 

 situated near the middle of the abdomen, but varies somewhat in 

 the different species ; in Oxyuris vermicularis it is almost within the 

 boundary of the upper third of the body. 



Genera: — Oxyuris, Rudolphi; Ptychocephalus, Diesing; = Pseu- 

 donymus, Diesing; Pharyngodon, Diesing; Mastigodes, Zeder; = 

 Passalurus, Dujardin ; Heteralds, Dujardin ; Subulura, Mohn ; 

 Cosmocerca, Diesing ; Thelastoma, Leidy ; Strep stostomum, Leidy ; 

 Allodapa, Diesing. 



