ALGUNOS TREMATODOS DE REPTILES DE MEXICO

Resumen

We have collected two species of the genus Polystoma from the urinary bladder of fresh-water turtles ; we consider one of this species new. We have also found in the large intestine of these turtles, one species of genus Schizaniphistomoides and one species of genus Cercorchis which we also consider with marked peculairities that warrant the erection of a new species.
The new species of Polystoma: already mentioned, is similar to P. orbiculare, P. opacum, P. floridanum and to P. exhamatum in the body shape but differs from them in certain important details as the presence of 19-20 hooks in the genital disc and the length of the intetinal caeca which reach the caudal disc.
Our new species Cercorchis dissimilis, is deprived of esophagus, therefore it presents a slight similarity to C. pleroticus, C. bifurcus and C. robustus but differs frorn them in the absence of prepharynx; in regard to the other species of Cercorchis, C. dissimilis presents neither esophagus nor prepharynx.
Renifer grandispinus n. sp. differs from R. kansensis in the length of the cirrus sac with regard to the acetabulum, in the size of the spines and in the length of the intestinal caeca; from R. ellipticus in the size of spines, the suckers and the eggs. This species was found in the esophagus of a snake Drymarchon corais melanurus.