THE NAUTILUS. 



141 



pines export about 320 tons annually. The more careful of 

 the Japanese fishermen save both meat and shell. From ten 

 tons of shell a ton of meat is obtained, worth in China £20 a 

 ton. Dried and smoked for two days, it is then ready for 

 export, and is considered a delicacy. — C. W. J. 



The Cercarial Infection of South African Snails. By 

 F. G. Cawston, M. D. (Reprint from The Medical Jour, of 

 S. Africa, 18 pp., 1917.) The species of snails harboring vari- 

 ous kinds of cercariaa are given, with special reference to 

 Physopsis africana, which harbors the Bilharzia cercariae. 

 After describing his work on this line, the following is part 

 of a summary : 1 ' The foregoing experiments and observations 

 would seem to show that the urine of a person who harbors 

 the Bilharzia parasite in South Africa becomes dangerous to 

 the community only when it reaches fresh water containing 

 specimens of Physopsis africana. It is interesting to observe 

 that the intermediary host of Schistosoma haematobium both 

 belong to the same subfamily of molluscs, LimncewKz, Phy- 

 sopsis africana in South Africa and Bullinus dybowski in 

 Egypt; that the intermediary host of Schistosoma mansoni 

 belongs to the Planorbincc — Planorbis boissyi in Egypt and 

 Planorbis guadelupensis in South America ; whilst the inter- 

 mediary host of Schistosoma japonicnm is Blanfordia (Kata- 

 yama) nosophora (Robson)." — C. W. J. 



Furesoens Molluskfauna, by C. M. Steenberg (D. Kgl. 

 Danske Vidensk. Selsk. Skrifter, Naturv. og Math. Afd., 8, 

 Raekke III, 1, 1917, pp. 78-200, Tar. I-VIII). A very ex- 

 haustive account of the bathymetric distribution and varia- 

 tion of the molluscan fauna of Fureso, a lake near Copen- 

 hagen, with a comparison of the bathymetric distribution of 

 the mollusca in other European lakes. A resume is given in 

 French. The illustrations are excellent. 



Anatomie des Acanthinula et des Vallonia. Les or- 

 ganes genitaux. Par C. M. Steenberg. (Vidensk. Meddel. 

 fra Dansk Naturh. Foren., Bd. 69, 1917.) The minute size of 



