Fossils from the Upper Musashino of Kazusa and Shimosa. 251 



Length. Height. Depth. 



Eight valve 9.2 miUini. 7.8 milHm. 2.6 miUim. 

 Left „ 8.1 „ 7.3 „ 2.3 „ 



This shell has not yet been reported from Japanese waters. 

 Fossil occurrence. — Shito (very common). 

 Living. — Off Mindanao of the Philippines at the depth of 82 

 fathoms. 



Genus VEI^EUITPIS, Lamarck. 



S37. Venet'iipis seiniptirpurea, (Dunker). 



PI. XII. Figs. 1, 2. 



Venervpis semipuiyurea. Pilsbry, Catal., p. 129. 

 Bupellaria se^nipioywea. Dnnker, lud. Moll p. 208. 



This shell which is more or less variable in outhne may be 

 described somewhat as follows: 



Shell usually rather thin, convex, transversely elongated, 

 oblong, inequilateral, rounded in front, more or less truncate 

 behind. Dorsal margin more or less straight and mostly parallel 

 with ventral . margin. Surface with a blunt edge running from 

 beaks to postero-ventral corner. The sculpture consists of numer- 

 ous, close, fiexuous, radiating riblets crossed by rude lines of 

 growth. Of the three teeth present in each valve, the middle 

 one is thick and bifid. Palliai sinus deep, reaching the middle of 

 the valves, wdth the upper border horizontal and the lower oblique, 

 so that the end becomes bluntly pointed. 



The variability of the shell lies in its length (sometimes 

 double, sometimes not quite one and a half times the height), in 

 the degree of the parallel state of the dorsal margin with the ventral 

 as well as of the inequilateral state and depth, in the shape of 

 the anterior end (rarely truncate), etc. 



The living specimens of this shell are coloured purplish in the 

 hinder part, while the remaining parts are more or less white. 

 Duuker in describing this species did not give any figure. 



The following are some of the measurements: 



