52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



U.S.N.M. no. 428582, 10 specimens received from Dr. Y. T. Yao, 

 of the central Field Health Station, National Government of the 

 Republic of China, collected at Sunkiang, Chekiang Province. 



U.S.N.M. no. 428580, 12 specimens received from the same 

 source, collected at Soochow, Kiangsu Province. 



U.S.N.M. no. 428577, 5 specimens from the same source, collected 

 at Wukiang, Kiangsu Province. 



U.S.N.M. no. 428581, I specimen from Kashing, Chekiang 

 Province. 



U.S.N.M. no. 428579, 7 specimens from Nanking, Kiangsu 

 Province. 



This species can be differentiated from the other two in which the 

 marginal teeth have 7 : 5 denticles, respectively, by being more broadly 

 conic and in having the ribs less strongly developed than Oncomelania 

 hupensis and more strongly developed than in Ocouielania elongata. 



ONCOMELANIA MULTICOSTA, n. sp. 



Plate I, fig. 16; plate 2, fig. 16; plate 5, fig. 6 



Shell elongate-conic, pale wax yellow, nuclear whorls decollated. 

 Early postnuclear whorls marked by slender incremental lines which 

 gradually develop into ribs. The later whorls well rounded, marked 

 by very regular, rather closely spaced slightly retractively slanting, 

 axial ribs, of which 21 are present on the last whorl behind the varix, 

 24 on the penultimate, 21 on the third from the last, 24 on the fourth 

 and fifth from the last and 10 on the sixth from the last, beyond 

 which they are lost. The spaces separating the ribs are about equal 

 to them ; spaces and ribs are marked by fine incremental lines. Suture 



