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 fuil 
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 
