THE TREMATODE PARASITES OF MARINE MAMMALS 



By Emmett W. Pkice 



Parasitologist, Zoological Division, Bureau of Animal Industry 

 United States Department of Agriculture 



The internal parasites of marine mammals have not been exten- 

 sively studied, although a fairly large number of species have been 

 described. In attempting to identify the trematodes from mammals 

 of the orders Cetacea, Pinnipedia, and Sirenia, as represented by 

 specimens in the United States National Museum helminthological 

 collection, it was necessary to review the greater part of the litera- 

 ture dealing with this group of parasitic worms. In view of the 

 fact that there is not in existence a single comprehensive paper on 

 the trematodes of these mammals, and that many of the descrip- 

 tions of species have appeared in publications having more or less 

 limited circulation, the writer has undertaken to assemble descriptions 

 of all trematodes reported from these hosts, with the hope that such 

 a paper may serve a useful purpose in aiding other workers in de- 

 termining specimens at their disposal. 



In addition to compiling the descriptions of species not available 

 to the writer, two new species, one of which represents a new genus, 

 have been described. Specimens representing 10 of the previously 

 described species have been studied and emendations or additions 

 have been made to the existing descriptions; in a few instances the 

 species have been completely reclescribed. 



Three species, Distoinwni pallassil Poirier, D. vaUdwim von Lin- 

 stow, and D. am/pidlacewni Buttel-Reepen, have been omitted from 

 this paper despite the fact that they have been reported from ceta- 

 ceans. These species belong in the family Hemiuridae, and since all 

 species of this family are parasites of fishes, the writer feels that 

 their reported occurrence in mammals may be regarded as either 

 errors of some sort or cases of accidental parasitism in which fishes 

 have been eaten by mammals and the fish parasites found in the 

 mammal post-mortem. Buttel-Reepen (1902) has pointed out, in 

 connection with the reported occurrence of D. ampullaceum in a 

 cetacean, that sailors commonly designate species of mackerel as 

 "Delphin" or "Dolphyn (holliindisch)." It appears likely, there- 

 No. 2936— Proceedings U. S. National Museum, Vol. 81. Art. 13 



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