S6 



It will be noted the spire varies from an extremely flattened 

 .type, such as is presented in morphs i6, 17, etc., to those in 

 which an elevated spire is present comparable to those found 

 in morphs 30, 37, etc. The sculpture likewise varies from a 

 rather imbricated condition to forms that are perfectly smooth. 

 The coloration follows the common pattern, with an integra- 

 ted sequence. 

 Specimens available, 200. , . 



Morph 14. Plate xxix. 



Prevost Harbor is a small bay on the northeast coast of 

 Decatur Island, in the San Juan group. The specimens illus- 

 trated were collected from a reef on the northern border of the 

 bay. 



This morph consists of individuals in which the spire is rela- 

 tively short, the sculpture is practically obsolete, and the 

 shells are devoid of color. Their rather large size suggests 

 favorable nutritive conditions. 



Shells of this type, which appear to represent an extreme 

 form as compared with the highly imbricate races, occur as 

 elements in many polymorphic clines throughout the range of 

 the species. 

 Specimens available, 25. 



Morph 15. Plate XXX. 



Ebey*s Landing is located on the western shore of Whidbey 

 Island, in Puget Sound. 



This morph is a variation of the smooth type in which th^ 

 sculpture is faintly indicated, and the color is very delicately- 

 banded. 

 Specimens available, 100. 



Morph 16. Plate xxxi. 



Canoe Bay is located on Vancouver Island, a short distance; 

 north of Sidney, B. C. 



This morph is evidently closely related to morphs 15, I7> 

 and many other populations in this area. 

 Specimens available, 100. 



