MARINE UNIVALVES 



157 



the coast of Lower California. This species has a 

 larger shell than that of the Livid Macron, and it 

 is also of a darker color. The aperture is very large, 

 the outer lip thin, and the canal a mere notch. Its 

 length is rather more than an inch. 



The large shell shown in 

 Figure 140 comes from north- 

 ern Alaska and it has re- 

 ceived several names. It will 

 be safe, however, to call it 

 Volutopsius kobelti^ D a 1 1, 

 Kobelt's Volutopsius. It is 

 not a common shell, and the 

 specimens that are usually 

 collected are often beach- 

 worn, but the picture repre- 

 sents the shell in perfection. 

 Its full length is about four 

 inches. 



Volutopsius castaneus^ 

 Morch, the Chestnut Volutop- 

 sius, is found more abun- 

 dantly than the last species. 



It lives in shallow water off the Aleutian Islands. 

 It is of a brownish color and it has no epidermis. 

 The aperture is large, the surface rough and des- 

 titute of any spiral sculpturing. It is about the 

 same size as the last species. 



Volutopsius attenuatus^ Dall, the Slender Volu- 

 topsius, shown in Figure 141, comes from Bering 

 Strait and the adjacent Arctic waters. The shell 



Fig. 140. X i"(*) 



