CHAMA, CARDIUM AND VENUS 75 



Protocardia centifilosa^ Cpr., the Hundred-Lined 

 Cockle, has a small, thin shell, whose surface is 

 sculptured with very many exceedingly fine lines. 

 The umbones are prominent, the outline circular, 

 with a diameter of nearly an inch. It ranges from 

 British Columbia to San Diego. A variety, rich- 

 ardsonii^ Whiteaves, reaches from the north to the 

 coast of Oregon. It is very small, and is rarely 

 found. 



We now come to the Veneracea^ a sub-order in- 

 cluding many of the most interesting shells to be 

 found along our coast. The typical genus of this 

 order is named Venus^ after the goddess of beauty, 

 but the old genus has been divided among many 

 names. The first shell to be described is Dosinia 

 ponderosa^ Gray, the Heavy Dosinia. Its real home 

 is near the equator, but it is found from Peru to San 

 Pedro Bay. The shell is nearly circular, about four 

 inches in diameter, pure white internally, but creamy 

 brown on the outside. It is very smooth, save for 

 concentric lines of growth, and the deep lunule is 

 heart-shaped. The shells are thin at the edges, but 

 very thick and heavy in the older parts. The pallial 

 sinus is V-shaped, and the ligament is external. 



T^ransennella tantilla^ Gld., the Little Transen- 

 nella, has a shell ranging from Vk X.o Vz oi an inch ' 

 in length. It is somewhat triangular, its surface is 

 very smooth and bright, its external color is white, 

 or perhaps marked with brown, while internally it is 

 white with a purple stripe at the posterior end. It 

 was formerly called Fsephis tantilla^ and it has also 

 received various other names. It ranges from Sitka 

 to Mexico. 



