REPORT ON THE SEALS. 137 



That Seals do take stones into the stomach has been observed both by the seal 

 fishermen and by naturalists. Captain Henry Pain, of the S.S. " Scanderia," when writing 

 upon the habits of the Sea Lion, says 1 that he has seen upwards of twenty-five pounds 

 weight of stones, some of which were the size of a goose's egg, in " a pouch " inside the 

 animal, obviously the stomach. He states that as these animals get thin they have the 

 power of throwing the stones up, a sufficient quantity only being retained to keep the Seals 

 from coming up too freely to the surface. Mr. Elliott relates 2 that he has opened the 

 stomach in many specimens of Callorhinus ursinus, and that in old bulls he has seen stones 

 which weigh half a pound, and in one stomach he found about five pounds of large 

 pebbles : he also possesses the stomach of a Sea Lion in which more than ten pounds of 

 stones were present, some of which weighed two and three pounds. Mr. Robert Brown, 

 in his account of the Pinnipedia of the Greenland Seas, 3 states that he has often seen 

 small stones or gravel in the stomach of the Walrus, and that this is a habit which 

 it possesses in common with PJwca barbata and even Beluga catodon. The intelfigent 

 keeper of the Seals in the Zoological Gardens, London, informs me that he is familiar 

 with this practice, and that he has seen the Sea Lion both swallow large pebbles and 

 subsequently disgorge them. 



Various uses have been ascribed to this peculiar habit of the Seals. The prevailing 

 opinion amongst sailors is that the animals swallow the stones as ballast to enable them 

 to dive so as to catch fish, and that they can at will disgorge them. Mr. Elliott 

 considers that their use is, by grinding against each other, to destroy the numerous 

 Nematode worms with which the stomach is infested. Others again maintain that they 

 serve the same purpose as the stones in the gizzard of a fowl, and assist in the trituration 

 of the food. I am myself inclined to favour this view, for a Seal literally " bolts " 

 entire the fish which serve as its chief food, without any mastication, and the action of 

 the pebbles on the fish so swallowed would without doubt, through the movements of the 

 muscular wall of the stomach, most materially assist the gastric juice in the trituration and 

 chymification of the food. 



1 Proc. Zool. Soc. Lond., 1872, p. 681. 



2 Quoted in Allen's History of North American Pinnipeds, p. 353. 



3 Proc. Zool. Soc. Lond., June 25, 1868, p. 430. 



(ZOOL. CHALL. EXP. PAET LXVIII. 1888.) Yj7 18 



