58 



Morph 20. Plate xxxv. 



Pleasant Beach is located on the southwest border of Bain- 

 bridge Island, in Puget Sound. The similarity of this morph 

 to morphs 21, 22 and 23, will be apparent. The coloration of 

 the shells in this population is for the most part of a pale 

 brownish tinge, with very inconspicuous banding. The sculp- 

 ture shades into an almost perfectly smooth form . 

 Specimens available, 150. 



Morph 21. Plate xxxvi. 



Wildcat Cove is an indentation at the northern border of 

 Samish Bay in Whatcom County, Washington. In this morph 

 we find conspicuous dark banding, with the usual range of 

 coloration, although the small numberof specimens available 

 does not include any of the pure brown forms. 

 Number of specimens available, 12. 



Morph 22. Plate xxxvii. 



Vashon Island is located in Puget Sound, about midway 

 between the cities of Seattle and Tacoma. The population 

 illustrated was collected at Paradise Cove, an indentation in 

 the southern coastline of the island. The shells in this morph 

 are very similar in sculpture and coloration to those seen in 

 morphs 19 and 20, which presumably indicates a comparable 

 genetic basis. 

 Specimens available, 25. 



In the same area there is a dock on the piling of which we 

 find a population of an entirely different type, as shown in 

 PlatexLviii. The shellsofthis morph are strongly imbricated 

 and are of great size, indicating favorable nutritive conditions. 



Morph 23. Plate XXXVIII. 



Deception Pass is the narrow strait which separates the 

 north end of Whidbey Island from the mainland. The speci- 

 mens illustrated were collected from a reef at the southern 

 end of the pass. 



