NO. 5 INTERMEDIATE HOSTS OF ASIATIC BLOOD FLUKE BARTSCII 53 



strongly constricted. Periphery well rounded. Base narrowly um- 

 bilicated, marked by the continuation of the axial ribs and incremental 

 lines, which extend into the umbilicus. There is a heavy varix behind 

 the peristome on the outer lip. Periphery broadly ovate, dark 

 edged, expanded and reflected and adnate to the preceding turn at 

 the parietal wall. The operculum is typically oncomelanid. The 



radula has the formula : 2-1-3 : 6: 5. 



The type, U.S.N.M. no. 420962, was collected by Dr. Fu-ching Li 

 at Wu Hsing, Chekiang Province, China. It has 6.6 whorls remain- 

 ing, and measures : Height 8.8 mm ; diameter 2)-7 nim- 



Three additional specimens, U.S.N.M. no. 420963, yield the follow- 

 ing measurements : 



U.S.N.M. no. 428585, six specimens received from Dr. Y. T. Yao. 

 of the Central Field Health Station, National Government of the 

 republic of China, collected at Hangchow, Chekiang Province. 



This species is readily distinguished from the other Oncomelanias 

 by its lesser number of denticles on the inner marginal and by having 

 the ribs much more regularly developed and spaced. 



ONCOMELANIA COSTULATA (Heude) 



1890. Hcmibia cosfulata Heude, Mem. Concern. Hist. Nat. Emp. Chinois, pp. 



169-70. 

 1924. Oncomelania hupcnsis Annandale, Amer. Journ. Hyg., Mon. Ser. no. 3, 



p. 285, in part. 



We have not seen specimens referable to this species and give a 

 free translation of Heude's description. Fie states that ligures of it 

 were accidentally omitted from his plate. 



It agrees with Oncomelania crassa Heude in height and is dis- 

 tinguished from all the other species by the more slender and more 

 numerous axial ribs, which is especially true of the last whorl. The 

 spire is elongate, pointed straight and almost entire. 



It was found in company with Oncomelania longiscata in the upper 

 mouth of Lake T'ong-t'ing, opjwsite the village of Kin-tcheoufou. 



