128 New York State Museum 



Cod. It is especially abundant between tides on the 

 rocks where barnacles occur for it is a carnivorous 

 form and feeds upon them. It is abundant on Euro- 

 pean shores as far south as Portugal and is an immi- 

 grant to American waters by way of Iceland and 

 Greenland. On our coasts it ranges from Long Island 

 to the Arctic ocean. The shell is never more than one 

 and one-half inches long here, but it is larger on the 

 northern coasts of Europe. Individuals are variable 

 in form and color, depending to a certain extent upon 

 the conditions under which they live. The color varies 

 from white through yellow to chocolate. It may be 

 banded with yellow or brown or rarely vermilion. The 

 exterior of the shell is smooth to exceedingly rough 

 and has numerous coarse revolving ridges. There are 

 several species of Purpuras in the Florida waters and 

 three species on the Californian coast. The Purpuras, 

 when mutilated, exude a reddish purple fluid. A 

 species (Purpura paluta) closely related to our Rock 

 Snail occurs in Mediterranean waters and was the 

 basis of the famous Tyrian purple dye of Roman days. 

 Periwinkles are also found on European coasts and are 

 exceedingly abundant on the rocky shores of England 

 where they are sold to the poor in the large cities. This 

 snail was introduced into American waters by way of 

 Iceland, Greenland and the Labrador coast. Cape Cod 

 was the southern limit of its range for many years, 

 but now it is reported as far south as New York. Vast 

 colonies of Periwinkles are found along the Maine 

 coast on rocks exposed at high tide. The shell of 

 L. littorea is dark brown in color, five-eighths of an 

 inch long, thick and heavy with a sharp pointed spire 

 and large body whorl. L. rudis is a smaller species 



