I'l.ATK li. 



Tampsia Ushopi Stephenson. Top view of the type group of individuals, about 

 eleven-twentieths natural size. Shows the features that characterize the 

 upper rim of the lower valve, including the slit or sinus (a) which cuts into 

 the shell along the anterior siphonal channel (E), the triangular depres- 

 sions which border the slit on either side, the broad, shallow depression 

 between the edge of the posterior siphonal notch ( S ) and the margin of the 

 inner cavit.v, and the impressions of the radial vessels. Cat. No. 32499, 

 U.S.N.M. Page 6. 



15 



