46 CALIFORNIA SEA SHELLS. 



venture however to illustrate two species, trust- 

 ing that the student will carefully notice the ine- 

 quality of the ears of the shell, and especially 

 the little notch beneath one ear, through which 

 the animal moors itself at times, by a series of 

 threads, called byssus, 



Pecten cequisulcatus, Cpr., Fig. 2, PI. XII, is 

 an inch or two in diameter, strong, full, brown- 

 ish, and marked by about twenty equal ribs. 



Pecten latiauritus, Conr., Fig. 3, PI. XII, is 

 very thin and delicate, having about iii'teen 

 rounded ribs. The ears are broad and unequal, 

 the shells but little arched, while the color is 

 brown, variously mottled with white like the 

 feathers of a hen ; size, from one-half to one inch 

 in diameter. These little shells live attached to 

 sea-weed ; occasionally a storm tears up the weed 

 and washes it ashore, thickly studded with these 

 little beauties. 



Pecten hastatus, Sby., is a much larger and 

 stronger shell, elongated, with very unequal ears, 

 many line, and a lew prominent ribs. Color, 

 pinkish. 



We now come to a notable California species, 

 Ilinnites giganteus, Gray, Fig. 4, PI. XII, some- 

 times called the Rock-oyster. In its early life 

 it has a free, symmetrical shell looking like a 

 Pecten. It is then distinguished by its very un- 

 equal ears, and the twelve prominent, serrate ribs 

 on the upper valve. It soon settles down for 

 life in some convenient and sheltered spot, such 

 as the inside of an old Haliotis shell, fastens its 

 lower valve to this support, and yields itself up 



