282 ILLINOIS BIOLOGICAL MONOGRAPHS [282 



yet none of these species are known to occur in more than one conti- 

 nent. The distribution of each species seems narrow. There are, how- 

 ever, but few records and the data are incomplete. When more records 

 are available it may be found that some of these species may have a far 

 wider distribution. In all the cases known the hosts are aquatic or 

 semiaquatic animals and they feed in part at least upon animals which 

 like themselves are aquatic or semiaquatic in their habits. It has not 

 been possible to work over the rather scant literature on the food habits 

 of these animals hence no data on that topic are here presented. It is 

 to be hoped that someone may make a study of the food of these hosts 

 and thus enable to be made a determination of the relationships of these 

 parasites to each other and to their hosts. 



An accompanying table gives the names of the parasites, their hosts 

 and the locality of the collection. In another table the parasites have 

 been grouped according to the order and family of the host. The latter 

 table shows that there are Proteocephalid species from Caudate and 

 Salientian Amphibians, from the Varanidae, a family of Lacertilian 

 Reptiles, and from three families of Serpentes (Ophidia). These fami- 

 lies are Boidae, Colubridae, and Viperidae. A single subfamily in each 

 of the Boidae and Viperidae furnish hosts for Proteocephalids while in 

 the family Colubridae one subfamily belonging to each of the three se- 

 ries furnishes host species. At the bottom of the table is placed a species 

 which tho reported to have been taken from a dog is certainly not a dog 

 cestode. Its nearest relatives, anatomically, are the Proteocephalids of 

 snakes and particularly the Proteocephalids of the Crotalinae. It has 

 been suggested elsewhere that the real host was probably one of the 

 Crotalinae. Because of the small amount of data it has not seemed 

 justifiable to draw many general conclusions in regard to these para- 

 sites. 



