22 THE SHELL-FISH OF THE COAST. 



ture, and its direct truncature ; but the base of the 

 inner side of the aperture shows more or less of a 

 fold, which is wanting in the whelk. These active 

 creatures of the tide-water pools, whose long and 

 slender foot constitutes so marked a feature of 

 their anatomy, offer an interesting study to the 

 lounger on the sands, and even if their habitat is a 

 little moist a pair of rubbers will readily bring you 

 to them without discomfort. Observe them gliding 

 along the surface of the mud, furrowing the soft 

 bottom with their extended foot. A few, possi- 

 bly, are floating, with the foot directed upwards. 

 The dog-whelk is decidedly predaceous in its habits, 

 boring rapidly through the shells of other mol- 

 lusks in quest of animal food, and creating gen- 

 eral havoc in its neighborhood. Indeed, it feeds 

 not only upon live ilesh btit upon dead flesh as 

 well, acting the part of a scavenger. Hence the 

 use to which this little creature has been put to 

 clean out the foul animal matter from aquaria. 

 Its own shell appears frequently pierced with a 

 hole, and rumor points towards cannibalism on the 

 part of tlie animal. One of the foreign dog-whelks 

 [Nassa reticulata) is known to prove exceedingly de- 

 structive to the oyster-fares of the French coast, 

 and so numerous is it that a single tide has yielded 

 upwards of 14,000 specimens on a shore area of 

 about 100 acres. This species has been known to 

 bore through the shell of a three-year oyster within 

 eight hours, and to destroy an oyster of a single 

 month in a half-hour. 



A large proportion of the dog-whelk shells of our 



