AKT. 17 PARASITES OF AMPHIBIA AND EEPTILIA HARWOOD 6 



testinal ceca extend nearly to the posterior end and are of the usual 

 type. The testis is located in the middle of the body. It is 0.3 to 

 0.33 mm long by 0.23 to 0.28 mm wide. The vas deferens passes 

 forward on the ovarian side of the body, median and dorsal to the 

 ovary. The terminal portion of the tube is enlarged to form a 

 seminal vesicle. The cirrus sac is 82/a to dOfi in diameter. The geni- 

 tal coronet contains 16 hooks. The ovary is lateral in position, 

 nearly spherical, and Q7fi to 85fi in diameter. The ootype is median, 

 ventral, and caudal to the ovary. As usual it receives the two vitello- 

 vaginal ducts. From it the genito-intestinal canal could be seen 

 extending to the intestinal cecum of the ovarian side. A few nuclei 

 around the ootype appear to represent Mehlis's gland. The vitellaria 

 are extensively developed in the lateral fields, but they leave the 

 intercecal space relatively free. The lateral fields converge just 

 posterior to the pharynx and again posterior to the most anterior 

 pair of suckers of the caudal disk. Between these lines the vitellaria 

 extend only slightly beyond the median border of the intestinal ceca. 

 The vaginae open at the lateral margins of the body, on the level 

 of or slightly anterior to the ovary. The sides of the body are 

 sharply indented at this point. The egg is 0.18 to 0.22 mm in diam- 

 eter. No specific characters were observed in the excretory system. 



Host. — Tejrapene caroliiia triunguis. 



Locality. — Houston, Tex. 



Habitat. — Urinary bladder. 



Type s;?e^mer?,.— U.S.N.M. Helm. Coll. No. 30864. 



Remarks. — This species is very similar to P. orhtculare and P. 

 floridanutn, but it is a smaller worm, and the vitellaria do not crowd 

 into the intercecal area posterior to the testis as they do in P. orhi- 

 culare and P. -fioridanum. Furthermore, the pharynx and cirrus sac 

 are much smaller in P. teiTapenis. 



POLYSTOMA (POLYSTOMOmES) MEGACOTYLE Stunkard. 1916 



In spite of slight differences from this form as described by Stunk- 

 ard (1917), I am referring a number of specimens from the mouth 

 of Pseudem.ys elegans to this species. Stunkard's material consisted 

 of three specimens from the mouth of Chrysemys tnarginata from 

 Creston, Iowa. A fourth specimen from the same host Stunkard 

 described as type and sole specimen of another species, Polystoma 

 microcotyle. Though the differences between the two forms were 

 distinct they were not very great, and my material shows many 

 intermediate forms. 



My material consists of eight adult specimens, and only the length 

 of the great hooks consistently varies from Stunkard's description. 

 The length of the great hooks varies from 140/x to 190;^ in mv ma- 



