112 WEST COAST SHELLS 



CUdiopliora punctata^ Cpr., the Dotted Pandora, 

 is a rare shell of very unusual shape, somewhat ob- 

 long and beaked. Instead of being inflated it is 

 very flat and compressed. The valves are thin and 

 silvery, while within they are marked with many 

 little pits or dots. It is somewhat over an inch in 

 length. From Victoria to San Diego. 



The last family of the Pelecypods is that of the 

 Boring-shells, of which there are two divisions. 

 The hrst of these include the Piddocks, which force 

 their way into clay, shell, or rock; while the second 

 division, the Teredos, work chiefly in wood. 



P hoi as pacific a^ Stearns, the Western Piddock, is 

 the first species to be mentioned. The shell is thin 

 and delicate, long and cylindrical, marked with 

 wavy, concentric ridges and faint radiating lines. 

 The sculpturing is not sharply divided into two sec- 

 tions as it is in some of the following species. With- 

 in each valve, beneath the hinge, is a slender spoon 

 of shell, very narrow and delicate; its use is not 

 fully known. On the outside, just above the liga- 

 ment, is a long protecting plate with straight sides. 

 This auxiliary valve, as it is called, is curved in 

 front and straight behind. The valves gape widely 

 at the ends. The length of the white shells of this 

 s[)ecies is about two and a half inches. The creature 

 burrows in mud and clay. It was first found on the 

 Alameda side of San Francisco Bay, but has since 

 been reported from the southern part of California. 



Pholadidea penita, Conr., the Common Piddock, 

 is shown in Figure 88. While it is often much smal- 

 ler than the picture, specimens are sometimes found 



