OYSTERS AND SMALL CLAMS 



6t 



Astarte polarls^ Dall, the 



Polar Astarte, is shown, 



somewhat enlarged, in 



Figure 33. This shell is 



more delicate than the 



last, with liner and more 



numerous ridges; it has a 



polished, light brown epi- 

 dermis. It comes from Fig. 33. xM*) 



Alaska, near the Shumagin Islands, also from Bat- 



hn's Bay on the Greenland coast. 



Figure 34 shows the ap- 

 pearance of the Esquimalt 

 Astarte, Astarte esquimalti, 

 Baird, which may be easily 

 recognized by its irregular 

 sculpturing, so clearly 

 shown in the picture. This 

 species ranges irom the 

 Aleutian Islands to Puget 

 Fig.34.xn*) Sound. 



Astarte vernicosa^ Dall, the 

 Varnished Astarte, Figure 35, is 

 a small species, its shell being 

 covered with a yellow-brown 

 periostracum and brilliantly pol- 



ished. It is found in Bering Sea. 



Fig. 35. X I (*) 



There are several other species ot 



this genus, living in northern waters, which will not 



be described in this book. 



Crassatella marginata, Cpr., the Margined Crassa- 

 tella, is a minute, southern shell, about the size of a 



