PL AN ORB IS 893 



Genus Planorbis Guettard. 



Definition. — As above. Shell discoidal, dextral, many whorled; 

 aperture crescentic. Peristome thin, incomplete; upper margin 

 projects. 



Type. — Planorbis corneus Linuceus. 



Planorbis boissyi Potiez and Michaud, 1838. 

 Synonym. — P. laurenti Bourguignat. 



Remarks. — This is the intermediate host of Schistosoma mansoni 

 in Egypt and the Sudan, ab discovered by Leiper. 



Planorbis olivaceus Spix. 

 This is the carrier of S. mansoni in Brazil. 



Fig. 466. — Planorbis olivaceus. The Carrier of Schistosoma mansoni 



IN Brazil. 



Genus Bulinus Adamson. 



Synonyms. — Naufa Leach ; Aplexa Fleming. Often spelt Bullinus. 

 Definition. — Planorbidae with ovoid shell, prominent spire, 

 branchia folded. 



Type. — Bulinus hypnorum Linnaeus. 



Classification. — The species of importance to us are: — Bulinus 

 contortus Michaud, 1829; Bulinus dyhowski Fischer, 1891; Bulinus 

 alexandrina Innes; Bulinus innesi Bourguignat. 



The above are the hosts of Schistosoma hcematohium in Egypt. 



Fig. 467. — Physa {Physopsis) africanus Krauss. A Carrier of 



Schistosoma Hcsmatobium^ 



