1901.] NATURAL SCIENCES OF PHILADELPHIA. 407 



thread-like concentric strise. Beaks moderately raised and full, 

 deeply eroded in adults. Interior whitish, or light violet outside 

 of the pallial line. Hinge rather narrow, the cardinal teeth 

 slightly grooved at their summits ; anterior and posterior laterals of 

 equal length, single in the left, double in the right valve. Length 

 33, ah. 27, diarn. 18 mm. 



Sado, Japan (Mr. Y. Hirase). 



It fills me with sadness to add another Corbicula to the Japanese 

 fauna, but these specimens cannot without violence be referred to 

 any of those known. C. martensi Clessin is perhaps the nearest, 

 but sadoensis is more transverse, the lateral teeth diverge at a wider 

 angle, and the striae are far closer. The very close, comparatively 

 fine striation is the chief differential character of the species, 

 distinguishing it from all the other forms. 



Corbicula awajiensis n. sp. 



Shell oval, compressed, the diameter about half and the alt. 

 three-fourths the length, bright yellowish green, with buff spots 

 and patches toward the beaks; strongly and regularly ribbed con- 

 centrically. Beaks rather low, not projecting much, eroded and 

 deep violet. Nearly equilateral, the anterior end sometimes slightly 

 narrower, the two ends about equally rounded, upper and lower 

 margins equally and similarly curved. Interior dark violet, with 

 a darker, often light-bordered spot under the beaks. Hinge deli- 

 cate, the cardinal teeth small; anterior and posterior laterals of 

 about equal length, somewhat curved, very strongly crenulate, 

 double in the right, single in the left valve. Length 16, alt. 12, 

 diam. 8-| mm. 



Noda, Awaji (Mr. Y. Hirase). 



The valve-margins viewed from within are seen to form a sym- 

 metrical oval figure, the upper and lower borders having almost 

 exactly the same curvature, and the anterior aad posterior ends 

 being about equal. There is no suggestion of the subtriangular 

 shape of most Japanese species of Corbicula. The beaks are low 

 and the sculpture strong and regular. It is a small species, the 

 first known from Awaji Island, and seems quite distinct from any 

 other. 



