50 CALIFORNIA SEA-SHELLS. 



with which it can dig or jump. Their siphons 

 are short, so they live near the surface ; they pre- 

 fer sandy bays, with shallow water. Cardium 

 corbis, Mart., Fig. 4, PI. XIII, is occasionally 

 found in San Francisco markets. It is very full 

 and round, and varies from one to three inches in 

 length. The ribs are slightly scaly, and number 

 about thirty. There is a sharp cardinal tooth, 

 and two laterals quite distant from the umbo. 

 Muscular impressions, two ; no pallial sinus ; 

 edge, strongly toothed ; color, whitish or light 

 brown. Large broken shells are often found on 

 the beach near the Cliff House. 



Liocardium substriatum, Conr., is a smooth 

 little Heart-shell from the southern part of the 

 State. It is half an inch long, of a light drab 

 color, dotted with yellow. Very fine lines of 

 growth may be observed with a glass, from which 

 circumstance it takes its name. It very much 

 resembles a sparrow's egg. Liocardium datum, 

 Sby., is a very large, smooth, yellowish Cockle 

 from the region of San Diego. 



A pure white shell, regularly marked by fine, 

 concentric lines is shown in Fig. 5, PI. XIII, 

 and is known as Lucina Californica, Conr. In 

 shape it is nearly circular, and varies from the 

 size of a dime to that of a half dollar ; the car- 

 dinal teeth are small, while the lateral ones are 

 strong. The ligament is external, and the small 

 lunule belongs wholly to the right valve. The 

 anterior muscular impression is long and narrow, 

 and the pallial line is entire. The pure white- 

 ness, symmetrical form, and regular markings 

 make this a very pleasing shell. It can often be 



