THE NEMATODE FAMILY GNATHOSTOMIDiE. 



251 



'•Length of tlie female six lines to an inch ; l)rea(lth to one 

 quarter of a line ; male from one-half to three-foiu tlis of the size. 



" frequent in tlie stomach of Emys sarrata, Emys reticulata, 

 Cistudo Carolina, and Kiiiosternitm jjeimsylvanicwm, adhering to 

 the mucous membrane in the same manner as Fhysalo-ptera 

 consti^icta" (vide infra, p. 272). 



I'iie general appearance, the shape of the lips, the ''funnels'' 

 of the caudal papillfe in the male, and the habitat and hosts all 

 suggest tliat this species is either identical with or closely allied 

 to ISpiroxys cantor la, but since the type of Leidy's species cannot 

 now be traced, the question must remain an open one. 



With regard to the SSpiroxys contort as of Seurat (1918), 



from the African tortoise, Clemmys leprosa, we find the descrip- 

 tion of this form somewhat difficult to understand. If our 

 interpretation of it is correct, Sen rat's worm difters from the 

 European species in the following points: — 



(1) the presence of an internal tooth on each lobe of each lip; 

 . (2) the presence of a pair of large papillse on the middle lobe 



of each lip, instead of one small papilla; 

 (3) the presence of an adanal, lateral pair of genital papill£e 



in the male ; 



(4j the presence of an accessory piece in the male. 



Specific Diagnosis. 



Spiroxys contorta (Rud,. 1819). 



A slender Spiroxys; the' lips without special armature, the tips 

 of the dorsal and ventral lobes, especially tlieir pulp, hooked 

 posteriorly; spicules ending in a, very fine point; caudal notch 

 of female lelatively coarse. 



2. Spiroxys gangetica*, sp. n. (Text-figs. 4-6; PI. II. 

 figs. 6-10.) 



We have examineil two batches of nematodes belonging to this 

 species, the one collected by Mr. Southwell from a host indentified 

 by him as Trionyx gav geticus, nnd the other .collected by one of 

 us (C. L.) from a tortoise killed in the Ganges delta, probably 

 Trionyx gaiigeticus. The two sets of speciuicns are specidcally 

 identical. 



This worm is stouter than the genotype. The head end tapers 

 much more gradually than the tail and is usuall}^ bent at an angle. 

 Close to either edge and near its base each lobe of either lio bears 

 a cuticular tooth on its inner surface (PI. II. figs. 6 & 7). 

 Each lip, that is, lias six teeth in addition to that characteristic 

 of the genus. In dorsal (or ventral) view the inner face of the 

 dorsal (or ventral) lobe is fiattened against its fellow of the other 

 lip, the cuticular teeth appearing from beneath near the angles 



* For specific diagnosis, see p. 253. 



