ART. 17 PARASITES OP AMPHIBIA AND EEPTILIA HARWOOD 



61 



ton (1927), however, has shown that the supposed differences in the 

 mouth capsules of these forms are not reliable, which is substantiated 

 by my material; and the spicules vary so widely as to be of little 

 systematic value in this case. Furthermore, as the spicules are very 

 difficult to measure, there is the possibility that Leidy's measure- 

 ments are inaccurate. For these reasons it seems best to allow Ma- 

 gath's name to sink into synonomy as Walton has already suggested. 



Table 2. — Length of spicules in Camallanus trispinosus from five different hosts 



Host 



Chdydra serpentina 



Kinoslernon mbrubrum kippocrepis. 



Pseudemys heiroglyphica..... 



Pseademya elegans 



Chrysemys picta.. 



Length 

 of short 

 spicule 



Microns 

 264-300 

 310-263 

 310-340 

 215-245 

 210-220 



Family GNATHOSTOMIDAE Railliet, 1895 

 Subfamily Spiroxyinae Baylis and Lane, 1920 



Genus SPIROXYS Schneider, 1866 



At present three species of this genus are knowm to parasitize 

 North American reptiles. These are Sp/'roxys constricta (Leidy), S. 

 eontorta (Rudolphi), and S. annydae Cobb. Furthermore, Walton 

 (1927) states that &, eontorta (Leidy) is not synonymous with 

 S. eontorta (Rudolphi), but Leidy's description seems to me to be 

 too inadequate to warrant any definite conclusion on this point. Two 

 of these are represented in my collection. 



SPIROXYS CONTORTA (Rudolphi, 1819) 



Walton (1927) reports finding representatives of this species in 

 the existing Leidy collection. The specimens that he refers to this 

 species were taken from the stomach of Chrysemys picta. I have 

 taken a Spiroxys, which I tentatively refer to this species, from 

 Pseudemys elegans and Deiroehelys retieularm at Houston, Tex., 

 and from Stemotherus odoratus at Huntsville, Tex. These worms 

 agree very closely with the description of S. eontorta (Rudolphi) 

 given by Baylis and Lane (1920), except that they all possess a 

 thickened, cuticular plate at the base of the lips on both the dorsal 

 and ventral aspects. The cephalic margin of each plate bears three 

 protuberances, which closely resemble papillae when the worm is 

 viewed from the lateral aspect. 



