82 



the family, triangular-ovate. The valves are convex. The anterodorsal margin 

 slopes downward and hence the anterior end of the larva is raised and some- 

 what pointed. The umbones are small and round. The shell is inequivalve, with 

 the right valve slightly more massive than the left and its umbo somewhat 



Figure 55: Veliconcha of Chalmys faireri nipponensis. 

 A — external view; B — rigtit ( 1 ) and left (2) valves; C — hinge of right ( 1 ) and left (2) valves. 



