60 ART. 2. S. TOKUNAGA. 



Area troscheli Dkr. strongly resembles this species, but the 

 anterior and posterior edges of the dorsal margin are more pro- 

 longed, and the number of ribs is only twenty four in a specimen 

 of 22™™ length. 



Oji (rare). 



The living specimens of this species were collected at 

 Kagoshima. 



U7. ARCA a SP. 

 PI. III. FigP. 22 a and 5. 



The present form seems to be a young of some species 

 of Area. It is only rarely found at ( )ji and is characterized 

 by the beaked shape, the form of the postero-dorsal angle, 

 the very small ligamental area and the oblique teeth. 



Living specimens were collected near Misaki (Sagami). 

 Length 9'"™ ; height 8""" ; breadth 7"'"'. 



14S. ARCA ß SP. 



This species frequently found at Oji is nearly rectangular, 

 the breadth very small and the posterior portion of the shell 

 much elongated. Length 15'"™; height 9"""; breadth '7.5™™. 

 Like the preceding it seems to be a young specimen of some 

 species of Area. 



ii9. ARCA r sr. 



This species abundantly found at ( )ji, but rare at Sliina- 

 gawa, has a nearly rectangular shape at the dorso-anterior edge ; 



