— 51 — 



This important form is represented by two closely related species in 

 California, Siliqiia lucida; ranging from Monterey south, and Siliqua 

 patula, found from Monterey to Alaska. As there are no important 

 differences one description will do for both. 



Description — The razor clam reaches a length of from four to six 

 inches but does not have the bulk of some other species because of its 

 slender form. It is markedly elongated though not to the extent 

 found in Solen and Tagelus, the valves are little arched and very thin 

 and delicate ; the periostracum is glossy and varnish-like in appearance. 

 The foot is large and powerful, the siphons rather short and united 

 except at the tip. 



Habitat and habits — The razor clam is found in the same locations 

 as is the Pismo clam, the pure sand beaches fully exposed to the 

 ocean and b}- preference those that are broad and level. Though 

 exposed to the same surf its valves are not massive as are those of the 

 Pismo clam, but the most fragile of all the larger clams. This 

 apparent contradiction finds its explanation in the surprising activity 

 of this clam ; its shell is specialized not for strength but for rapid 

 progress through the sand where the heavy and l)ulky shell would be a 

 hindrance. The method of burrowing, though not different in princi- 

 ple from tliat of other clams, is so highly developed that an account 

 of it. may be given. Some idea of their agility may be gained from 

 the statement that simill razor chims placed on wet sand have coiiiph^tcly 

 Iniried tlu^mselves l)y eight or ten movements of the foot in a period 

 as short as seven seconds. That the reaction of digging is a deep- 

 seated and fundamental one is shown by the fact that when a small 

 specimen is cut in two by the shovel the foot-bearing end will in some 

 cases bury itself almost if not quite as promptly as the uninjured 

 animal. When first thrown out on the sand the burrowing movements 

 of the foot may readily be seen thongh they are so rapid that it is 

 hard to make out all the details. The foot is first extended by a 

 series of movements until it projects half the length of the shell. This 

 (-■xtension is accomplished by forcing blood into cavities in the foot, thus 

 dilating it. As it is being extended the tip of the foot has a pointed 

 shape; in this way it penetrates the sand readily. Having reached its 

 full extent the tip continues to swell up until its cross section is 

 greater than that of the shell. This crowds against the surrounding 

 sand and when the muscles of tbe foot cantract, pulling the tip nearer 

 the body, the shell moves more readily through the sand than does the 

 foot and hence is drawn after it. Repeated in rapid succession this 

 serves to take the animal out of harm's way. In fact, if the first 

 spade thrust does not cut off the razor clam's retreat and turn it out 

 on the sand it is almost hopeless to follow it. At times the young, at 

 least, move horizontally just below the surface of the sand, burrowing 

 along in the manner just described witli the liinge uppermost and 

 leaving a furrow in the sand often a foot in length. How extensively 

 and for what purpose they thus move about is not known. 



During its presence at the surface of the sand, the animal holds a 

 vertical position, with the siphons projecting into the water or air 

 above, and tlie valves usually oriented in a definite manner with 

 relation to the water which flows over it, namely with the hinge toward 



