Volume I. May, 1898. Number 6. 



ZOOLOGICAL BULLETIN. 



ON THE OCCURRENCE OF DISTOMUM OVOCAU- 

 DATUM VULPIAN IN AMERICAN FROGS. 



\V. S. NICKERSON. 



IN the spring of 1893, the writer found a number of speci- 

 mens of this trematode inhabiting the Eustachian recesses of 

 the American frog, Rana clamata. At that time no satisfac- 

 tory description with figures of D. ovocaudatum had been 

 published, and I was therefore unable to determine positively 

 whether or not the worms which I had discovered were of that 

 species. A comparison of the American worms with speci- 

 mens of D. ovocaudatum preserved in the collection of the 

 Zoologisches Institut in Leipzig has shown me conclusively, 

 however, that the two are identical in all important characteris- 

 tics. I believe that the occurrence of this species in America 

 has not been reported heretofore. 



Previous writers, with the exception of Sonsino, have 

 described this worm as being found only under the tongue of 

 the frog. Sonsino ('93) reports finding it not only under the 

 tongue, but also in the stomach and first part of the intestine, 

 and in a single case in the lung. There is nowhere mention 

 of its occurrence in the Eustachian tubes. In the American 

 frogs, however, this seems to be its normal place of attach- 

 ment, and in living frogs I have never found it in any other 

 position. In a few cases I have found worms lying unattached 

 in the mouths of frogs which had been killed by chloroform, 

 but in such cases it is probable that the action of the chloro- 

 form had caused them to loosen their hold, though I have no 

 means of knowing what their place of attachment had been. 



