105 



using the latter to envelop the posterior part of the 

 abdomen of its prey. The radula was then brought into 

 action, and a hole was bored through the chitinous 

 exoskeleton until the proboscis could reach the muscles. 

 Here again the use of the foot as a grasping organ may 

 be noticed. In its turn the whelk must fall a prey to 

 many other inhabitants of the sea, and one often wonders 

 what has happened to the former owners of the numerous 

 whelk shells now found occupied by hermit crabs (see 

 Text-fig. on p. 98). 



The cod feeds to a certain extent upon the whelk, 

 though this is by no means its chief food. Remains 

 of the whelk have also been found in the stomach 

 of the dog-fish. Curiously enough, in most cases these 

 remains include only the fleshy part of the animal 

 and the operculum. This implies that, contrary to 

 expectation, the fish either bites off the protruding part 

 of the whelk or otherwise achieves the apparently 

 impossible in removing the animal from its shell. 



Quite recently, Dr. C. G. Joh. Petersen has published 

 a very interesting paper on the relations of the whelk to 

 the fisheries of Denmark. In 1909 a committee was 

 formed in that country to consider the harmful animals 

 of the sea-fisheries ; and five animals were black-listed — 

 the sea scorpion, the stickleback, crabs, starfish, and 

 whelks. Petersen suggested that before money was spent 

 on efforts to exterminate these creatures, experiments 

 should be made to determine the possibility of such a 

 proceeding. The whelk was selected for the experiments, 

 and the Board of Agriculture allotted funds for the work. 

 The harm done by the whelks was known and had been 

 investigated some time earlier (1895). It had been found 

 that the whelk attacked the plaice entangled in fishing- 

 nets. Although unable to seize activelv-moving fish, 



