ON JAPANESE SPECIES OF CORHICULA. 



157 



what triangular outline. It is further distinguished by the moderately 

 fine rib-stria?, the long straight lateral teeth, rough nymphs, and the 

 rather light structure for so large a shell. It does not seem to be a 

 common mussel ; I have seen only the type lo', sent by Mr. Iwakawa, and 

 several shells collected by Mr. John B. Henderson. 



Corbicula japonica Prime. 



C. japonica Prime, Annals Lyc. etc., VIII, p. 68 (Japan, Gulick). 



C. biformis Reinh., Jahrb. d. Malak. Ges. 1878, p. 189, pi. 5, fig. 3. 



Tokyo (Rein); Tokushima, Awa (Iwakawa). Distinguished by its 

 partly smooth exterior, which has irregularly spaced riblets on the lower 

 half and on the anterior end. The beaks are much smaller than in C. 

 sandai, and the hinge is narrower. 



Corbicula sandai Reinhardt. Plate VII, fig. 17, 18. 



Jahrb. d. Malak. Ges. V, 1878, p. 187, pl. 5, f. 2. 



Kyoto (Rein) ; Lake Biwa and Seta, Orni; Sendaigawa and Kago- 

 shima, Satsuma (Iwakawa and Hirase). 



Known by its large, high and inflated beaks and strong teeth. It 

 varies from yellowish olive to black externally, violet or white inside, or 

 in some places it is yellow or olive -yellow outside, pinkish white with 

 salmon-tinted border within. This light form often has violet stains on 

 the teeth. 



This species has not been found north of Lake Biwa. 



Some small and very pretty specimens were taken with C. snudai at 

 Sendaigawa, Satsuma. They are nearly smooth near the beaks, which are 

 not worn. The outside is light yellow, largely covered with black zones 

 and hair-like radial lines forming rays. The interior is white, with a yellow- 

 ish tint at the basal margin. The posterior end is broadly and indistinctly 

 truncate. 



