150 -^^i- 1 — M. Yokoyama. 



Ve7ius isahellina. Pliilippi, Zeitscbr. f. Malak,, p. 188, no. 65. Abbild., II[, p. 83, no. 

 5. Venus, pi. X, fig. 5. Pfeiffer in Syst. Concb. Cab., XI, pt. 1, p'. 194, pi. 25, 



fig. 9. 

 Venus foliacea. Toknnaga, Foss. Env. Tokyo, p. 46, pi. Ill, i\.g. d, {won V. fol iacea 

 Pbil). 



Toknnaga mistook this shell for Chione foliacea Phil, which 

 has the inner margin crenulate and not smooth as in the present 

 species. The shape is also somewhat different, the height heing 

 somewhat greater in Chione isabelUna. 



Fossil occmTence. — Otake (rare), Shisni, Tega. Oji and 

 Shinagawa in Musashi. Lower Mnsashino of Naganuma. 



Living. — Japan (according to Dunker). China Sea. 



336. Chione miiuïaiietisis, Smith. 



PL XI. Figs. 2, 3. 



Venus {Chione) viindanemis. Smith, Challenger Keport, Lamellibr,, p. 130, pi. Ill, 

 figs. 4, 4 b. 



The shell is small, rather thin, moderately convex, inequi- 

 lateral, subquadrate in outline, the four sides being formed by the 

 postero-dorsal, posterior, anterior and ventral margins, of which 

 the first is the shortest and the last the longest. The antero-dorsal 

 and anterior margins together form a curved line, while the 

 posterior is only slightly arched, meeting with the ventral usually 

 in a rounded right angle. The surface has a blunt edge running 

 from the beak to the postero-ventral corner, the part behind which 

 is slightly depressed in the middle. The sculpture consists of 

 radiating riblets and concentric lamellae. The former are rounded 

 and generally furnished with an interstitial one which is either 

 indistinct or obsolete near the beaks, while the latter are elevated, 

 variable in number, and at unequal distances from one anotlier. 

 Lunula longly ovate, distinctly bordered b}" grooves and ornamented 

 with a few radiating riblets. Shell-margin finely crenulate. Teeth 

 three in each valve, the middle one being the strongest. As to 

 the laterals, there is only one in the anterior part uf the right 

 valve, which is thin and rudimentary. Palliai sinus very shallow,, 

 broader than deep, narrowed at end. 



