— 54 — 



extent of the beds renders it entirely probable that even use by campers 

 and tourists in addition to the local population will be sufficient to 

 threaten their existence. The testimony everywhere was of depletion. 



There appear to be few beaches favorable for the transplanting of 

 this clam. The sandy beaches south of Humboldt Bay are too high 

 and well drained, with too small an area. The same is true of most of 

 the beaches in northern California. Small beaches alternating with 

 rocky shores are usually not suitable because of the small depth of the 

 sand, and the frequent presence of rocks. 



In conclusion we may say that this fine clam is not abundant enough 

 to support commercial digging; in northern California it will supply 

 a limited local demand, south of San Francisco its possilnlities and 

 present use are still more limited. 



DISH SHELL 



Spisula sp. 



At least two southern species of the genus Spisula, S. catilUformis, 

 the dish-shell, and S. hcmpliiUi, reach lengths of five or six inches and. 

 would be of economic importance if abundant enough. They have 

 valves which are thin, particularly at the edges, the brownish peri- 

 ostracum is conspicuous and the ligament is internal. Their use has 

 not been observed. 



GAPER 



Schizothairiis nuttnUi Conrad 

 Plate 16, figure 3 



Other names — Summer clam ; horse clam ; otter shell. 



This species is known under a variety of names. The one here used 

 refers to the gaping of the shell at the siphonate end; the term 

 summer clam is due to the belief of the Indians that they are best 

 during the summer months. It is occasionally confused with the 

 geoduck. 



Description — This is the largest clam in California waters wath 

 the exception of the real geoduck, which is nowhere abundant. The 

 shell reaches a length of from six to eight inches and the clam may 

 weigh as much as four pounds. The shell is thin and easily broken 

 and incapable of closing completely enough to retain the moisture 

 inside the valves. The great siphons can not be retracted entirely 

 into the shells because of their length and size; their heavy epidermis 

 affords them the protection which the shell fails to give. The foot 

 is small and apparently of slight use to the adult. The shell may 

 readily be recognized by its large size, gaping siphonate end, deep 

 ]iallial sinus and internal ligament. 



Habitat and habits — As might be inferred from its structure the 

 clam is found deeply buried, lying from a foot ;',iid a half to three 

 feet deep, depending upon the nature of the bottom, and usually in 

 such localities that it is seldom left exposed at mid-tide. It is thus well 

 out of harm's way while ample communication with the surface is 



