Vol. XII. February, 1907. No. 



BIOLOGICAL BULLETIN 



THE HABITS AND MOVEMENTS OF THE RAZOR- 

 SHELL CLAM, ENSIS DIRECTUS, CON. 



OILMAN A. DREW. 



Many of the older naturalists have called attention to the sen- 

 sitiveness and remarkable activity of this form, and the conse- 

 quent difficulty that is sometimes experienced in capturing it. 

 Some of the observations are not strictly accurate but they 

 have served to call attention to its adaptation for a burrowing 

 life. Even the uncommon shape of the animal indicates this 

 adaptation 



The species under consideration is to be found more or less 

 abundantly all along the eastern coast of the United States. It 

 is best known on sandy flats from which most of the water flows 

 at low tide, where specimens may be dug with spade or clam- 

 hoe. In some localities, as in restricted areas around Woods 

 Holl and North Falmouth, Massachusetts, where most of these 

 observations were made, the animals are quite abundant, and in 

 such places one may find the protruding posterior ends of the 

 shells, or see the siphon openings of the undisturbed individuals. 

 They readily take alarm and even a slight jarring of the mud of 

 the bottom in their vicinity serves as a signal for them to in- 

 stantly disappear. It is this sudden disappearance that has 

 attracted wide attention, and has given the impression that the 

 animals are exceptionally hard to capture (5 and 6). 



The species is probably not restricted to very shallow water. 

 Specimens are not often taken in a dredge, but the position that 

 they occupy buried in the rather hard sand or mud of the bottom, 

 makes their capture unlikely. Young specimens, from a milli- 

 meter to a centimeter in length have been taken in large numbers 



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