154 



HENRY A. P1LSBRY. 



M£.ey to Species. 



I. Nymphs strongly roughened (see the text-figure on p. 155.) 



a. Shell oval, coarsely ribbed, the hinge-line arched. 



b. Cavity of the valves white or violet-tinted, becoming deep violet below 

 the palliai line ; beaks moderately projecting ; shell of medium size. 



C. leana Prime. 



b'. Interior purple ; beaks very low ; upper margin of valves not more arched 

 than the lower margin ; shell small and delicate. C. awajiensis Pi Is. 



a . Shell subtriangular, the valve-borders straightly sloping fiom the beaks ; lateral 

 teeth long and straight ; exterior rather finely ribbed ; size large. 



C. orlhodonla Pi's. 



II. Nymphs nearly smooth, only minutely roughened. 



a. Exterior partly smooth on the convex or median ponion of the valves. 



b. Shell oval-triangular. C japouLa Prime. 



b' . Triangular, the beaks very 'arge and prominent ; hinge very strong. 



C. saitdai Reinh. 



a. Exterior coarsely ribbed; interior violet, paler or whitish in the cavity ; cardinal 

 teeth oblique ; length 27, alt. 23.5, diam. 15.2 mm. C. viola Pils. 



a" . Exterior densely striate or rib-striate. ~ 

 6. Shell oblong, with low beaks and low-arched hinge-margin. 



C. sndoensü Pils. 



b'. Shell subtriangular, with prominent be.iks and more angular hinge-margin. 



C. nipponensis Pils. 



There is another species, or group of closely related species, which I 

 have not seen, though they are from around Yokohama. This species or 

 group has received the following names: (ij C. f risenta var. atrata 

 Reinh., renamed C. Martcnsihy Clessin ; (2) C. donit ziana Cless. ; (3) C. 

 transversa Cless.,= C. oralis Reinh., and perhaps the same as C. Yoko- 

 haiuensis Sowerby (Coiie/i. Icon. XX, pi. 12, fig. 55). 



The collection from the Imperial Household Museum contains the 

 following species : 



