158 



WEST COAST SHELLS 



is thin, white and delicately striated. The length 

 is a little over two inches. 



Fig. 141 (*) 



Fig. 142, X i (*) 



hiomesus nux^ Dall, the Arctic Nut-shell, shown 

 in Figure 142, is well named, for it much resembles 

 a round, well-filled nut. It also comes from far 

 northern waters, the home of so many species of 

 mollusks. The shell is dark-colored, with a creamy 

 white layer above. In lite there is a periostracum 



which resembles velvet. 



hiomesus canaliculatus^ Dall, 

 the Channelled Nut-shell, is shown 

 in Figure 143. It is another north- 

 erner, and its white shell is covered 

 with a velvety epiciermis. Its 

 length is 35 millimeters. 



The next genus of shells that 



we are to consider has long borne 



Fig. 143 (*) the name of Nassa, a word which 



