1888.] NATURAL SCIENCES OF PHILADELPHIA, 127 



Entozoa of the Terrapin. — Prof. Leidy stated that he had on one ■ 

 occasion examined eight of our much esteemed food Terrapins, to 

 ascertain the character of their parasites. All were found to be in- 

 fested with an Echinorhynchus, living in the small intestine and 

 clinging by the thorny head to any part of the canal. The worms 

 ranged from six to sixteen lines in length and in numbers from five 

 to upwards of two hundred. The species is Echinorliynchus havmla- 

 tus originally described from several of our fresh water turtles. 

 {See these Proceedings 1856, 48.) 



In three of the Terrapins occurred a red thread worm, also living 

 in the small intestine and associated with the former, and like them 

 clinging, by their armed mouth, to the mucous membrane. The 

 species is the Ouculanus microcephalus, the males up to nine lines, 

 the females from twelve to sixteen lines. In one Terrapin there 

 "were eight, in a second over a hundred, and in the third upwards of 

 several hundred. They extended all along the intestine but were 

 most numerous at its upper part. The females are viviparous and 

 contained living young. 



In one Teri-apin only, also in the intestine, there were two flukes, 

 the Amphidomum grande, about half an inch long. 



In the bladder of another Terrapin there was a single Polystomum, 

 3'5 mm long, probably P. ohlongum, first described by Prof Wright, 

 of Toronto, from an individual obtained from the bladder of the 

 Musk Turtle, Aromochelys odoratus. 



In another Terrapin he had found four Polystomes of which three 

 Avere in the throat and the other in the nose. These pertain to a 

 different species from the former and may prove to be the Polystomum 

 ocellatum, found in a similar position in the European Turtle, Emys 

 europaea. At the genital outlet of Polystomum situated ventrally 

 at the fore-part of the body, the cirrus is surrounded by a circle of 

 hooks. In P. integerrimum, the species best known, and found in 

 in Europe, living in the bladder of Frogs, the genital circle is com- 

 posed of eight hooks. Prof. Wright ascribes sixteen hooks to the 

 circle of P. ohlongum, and this accords with the number in the 

 Polystomum fi-om the bladder of the Terrapin. In the other Poly- 

 stomes of the latter he found the circle to be composed of thirty-two 

 hooks. Siebold says there are forty hooks to the circle in P. ocella- 

 tum. Dr. Zeller figures the latter, from a sketch of Siebold, in 

 which the caudal disk is represented as having two large hooks and 

 eight small ones between the posterior j)air of bothria. In the allied 

 Polystomes of the Terrapin the number and arrangement of the hooks 

 of the caudal disk is the same as represented in Prof Wright's figure 

 of P. ohlongum,. If then we have a correct record of the facts, the 

 Polystome of the fauces of our terrapin may be regarded as another 

 species which may be distinguished as follows : — 



Polystomum coronatum. Body Avhen elongated lanceolate. 

 Caudal disk wider than the body, cordiform, with three pairs of 

 bothria and with the body attached between the anterior two pairs ; 

 changeable in form to oblong, circular or quadrate ; with three pairs 



