42 



WEST COAST SHELLS 



distinct ribs. The ears of the shell, by which we 

 mean the flattened parts on each side of the umbo, 

 are broad and pointed. The color is white and 

 brown. 



A variety of this species, known as 

 var. monotimeris^ Conr., is shown in 

 Figure 21. It is sometimes described 

 as a distinct species. The shell is 

 very thin and delicate, the ribs 

 Fig. 21 rounded anci rather faint, and the 



ears are smaller than in the last form. The colors 

 incline to yellow and brown, variously mottled with 

 zigzag lines of white. I have found this variety 

 living at San Pedro, and at times it is abundant as 

 far north as Carmelo Bay, near Monterey. There 

 are also several other varieties of this species. 



Pecten davidsoni^ 

 Dall, Davidson's Pec- 

 ten, is represented in 

 Figure 22, the form 

 and sculpture of both 

 valves being plainly ^'^' ^^' "" ' ^^'^ 



shown. The left valve has twenty-one rounded ribs, 

 while the right is nearly smooth. The color is waxen 

 white. It was dredged from deep water off Alaska, 

 and in Bering Sea. Very few of us, probably, will 

 ever have a specimen in our cabinets, but how inter- 

 esting it is to know what creatures are living at this 

 moment on the bottom of that cold ocean far to- 

 wards the North Pole. 



Pecten randolplii^ Dall, Randolph's Pecten, was 

 obtained by the U. S. Fish Commission from deep 



