MARINE UNIVALVES 



147 



Figure 121 represents two specimens of Buccinuin 

 angulati/m , Gray, the Angled Whelk. The pictures 

 are none too large, for the shells are strong and ro- 

 bust. Both of them represent females, for the shells 

 of the males of the same species are materially 

 smaller. This species lives on the shore of the polar 

 sea, near Bering Strait, and in the Arctic Ocean. It 

 represents a decidedly frigid type. 



Buccinum aleuticum^ Dall, the 

 Aleutian Whelk, Figure 122, has 

 a thin, six-whorled shell, of a pink- 

 ish color with a white pillar. It is 

 covered with a thin epidermis, 

 somewhat bearded. The sculpture 

 consists of fine, close-set grooves, 

 with spaces between them. The fig- 

 ure is slightly magnified. 



Buccinufn percassuni^ Dall, the 

 Thick-shelled Whelk, is shown in 

 Figure 123. This solid little shell 

 is found in the waters that bathe 

 the shores of Bering Island, a name 

 that makes us think of seal-skins 

 and refrigerators. The operculum 

 is remarkably distinct, and the shell 

 is decidedly thick and solid. 



Two specimens of Buccinum cas- 

 taneum^ Dall, the Chestnut Whelk, 

 are shown in Figure 124. The 

 left-hand figure represents the 

 normal form of this large shell, 

 while the other is the form with Fig. i23(*) 



Fig. 122, X ^ (*) 



