1919] Cort: The Ccrcaria of the Japanese Blood Fluke 489 



the cercaria of S. mansoni. Lutz (1916, p. 387) considers Planorhis 

 bahiensis to be a synonym of Planorhis olivaceus Spix. In a foot- 

 note to a review of Lutz's second preliminary report (Trop. Dis. Bull., 

 11, 79) Leiper makes the following statement: "Planorhis guade- 

 lupensis more recently implicated by Iturbe in Caracas is very similar 

 to, if not identical with, Planorhis olivaceus." The solving of the 

 exact systematic relations of these hosts will have to await further 

 work. As can be gathered from this brief review of the literature 

 there still remains much work to be done on the larval stages of the 

 human schistosomes. 



Studies on the human schistosomes are of peculiar importance to 

 California and the other Pacific coast states on account of immigration 

 from countries where schistosomiasis is prevalent. Records of the 

 United States Public Health Service and case records show that schis- 

 tosomiasis has been brought into this country. If suitable inter- 

 mediate hosts could be found this disease might become established, 

 especially since it can develop in cats, dogs, rats, cattle, and other 

 animals. In previous publications I have pointed out this danger and 

 have shown that trematodes of this type show considerable adaptability 

 in intermediate hosts (Cort, 19186, 1918c). Recently Reed (1918) has 

 also considered this subject. He discusses five cases of schistosomiasis 

 from California and mentions others which have come to his attention. 

 Hi.s conclusions in regard to the dangers ton California from this 

 disease are similar to my own. One of the purposes of the present 

 paper is to aid investigations, which are being carried on to determine 

 whether the human schistosomes have found suitable intermediate 

 hosts in this country, by clearly defining the cercaria of S. japonicum. 



MATERIAL 



The material of the larval stages of S. japonicum on which the 

 studies included in this paper are based was obtained from living 

 specimens of the Katayama snail, Blanfordia nosophora (Robson), 

 which were sent to Professor C. A. Kofoid by Professor A. Fujinami 

 of Kyoto, Japan. To both of these gentlemen my sineerest thanks are 

 due for making possible this work. Blanfordia nosophora is an oper- 

 culate snail, and is very resistant to drying. The snails were shipped 

 across the Pacific Ocean in dust, and appeared, on arrival, to be 

 entirely dry and dead. They were placed in water in an aquarium 

 in the evening and the following morning were found to be actively 



