A SYNOPSIS OF THE TREMATODE FAMILY SCHISTOSO- 

 MIDAE, WITH DESCRIPTIONS OF NEW GENERA AND 

 SPECIES 



By Emmett W. Price 



Of the Zoological Division, Bureau of Animal Industry, United States Depart- 

 ment of Agriculture 



The family Schistosomidae is composed of a number of genera of 

 diecious trematodes parasitic in the blood-vascular system of warm- 

 blooded vertebrates. The manner in which the free-swimming larval 

 forms gain access to the body (skin penetration by the cercaria) is 

 correlated with the fact that many of the species are parasitic in 

 aquatic birds, as these birds are naturally exposed to attack in cer- 

 caria-infested waters. Several species are of considerable medical 

 and veterinary importance; three species are parasites of man, and 

 several species occur in ruminants and other domesticated animals. 

 The forms found in man may produce severe lesions in the liver, 

 bladder, and intestine, frequently resulting in death ; those occurring 

 in the domesticated animals produce similar lesions, but as these 

 forms have not received as much study as the human species, less is 

 known of their medical and economic importance. 



Little is known of the distribution of schistosomes in the United 

 States. Tanabe (1923) described a new genus for a new species 

 which he succeeded in rearing in white mice following exposure to 

 infection with cercariae obtained from Lymnaea palustns in Boston, 

 Mass. ; Chapin (1924) reported a blood fluke from Marila affinis; and 

 more recently Linton (1928) described an Ornithohilharzia species 

 from water birds at Woods Hole, Mass. Several cercariae of the 

 schistosome type have been described from snails in this country 

 and it appears probable that these trematodes are not uncommon but 

 have been overlooked because of their peculiar location in the body. 



In this paper three new genera and species are described from 

 North American hosts, and Bilharziella polonica is reported from this 

 continent, apparently for the first time. As a result of the study of 

 these forms, it became apparent that a synopsis of this group would 

 be useful, as the descriptions of many species have been given in 



No. 2789.— PROCEFo.:iGS U. S. National Museum, Vol. 75, Art. 18 



8S876— 2!) 1 1 



