PEBBLE-SWALLOWING ANIMALS. 
31 
which selects flint for its gizzard if it can get it. This is so well 
known to poultry farmers that “Flint-grit for fowls ” is kept in stock 
at many seed-shops). 
As most of the flsh-eating creaJtures either swallow their prey whole 
or in chunks, and are also terrible gluttons, a great strain must be 
thrown on their digestive organs, and there is little or no doubt that 
these pebbles are useful in breaking up the food by acting as a crushing 
mill, and thereby greatly facilitating the process of digestion. This 
appears to be the most reasonable solution of this interesting question, 
and in accordance with the observed facts. 
As regards its application to Geolog}’’, it explains the presence of 
small quantities of pebbles in deposits to which they are foreign 
(especially when associated with animal remains). These have 
frequently been hitherto accounted for by various theories (such as 
drift, (fee.) of an inconclusive and unsatisfactory character. 
SUMMARY. 
A Summary of the principal points in this paper may be of 
service : — 
1. — That there is abundant evidence from various sources that 
sundry animals, both fossil and recent, have acquired a habit of 
swallowing stones, sometimes in considerable quantities. 
2. — That the animals addicted to this practice were fish-eaters, and 
were also partially or entirely deficient in true molars, or crushing 
teeth. 
3. — That the stones found in or with these animals are nearly all of 
the same character as regards their composition and color, an enormous 
majority being either white or pale-colored Silica. 
4. — That this clearly indicates they were not taken indiscriminately, 
but purposely selected. 
5. — That the only purpose for which they could have been useful 
was as an aid to digestion, somewhat analagous to the well known 
action of the gizzard-stones in graminivorous birds. 
The following is a list of animals reported as “ stone swallowers ” : — 
Reptiles — Plesiosaurus, Mauisaurus, Peloneustes, Elasmosaurus, 
Teleosaurus, Crocodile. Cetacea and Fishes — Seal, Sea-lion, Walrus, 
Dolphin, Porpoise, Shark, Dog-fish, Cod, Hake, Sting-ray. Birds — 
Penguin. 
(It has been further reported that pebbles resembling “ stomach- 
stones ” have been found with remains of Brontosaurus and 
Diplodocus, but as no definite details have as yet come to hand, these 
giants can only be mentioned provisionally). 
This list, as well as the evidence in connexion therewith, might be 
extended, but as it is possible that the matter before you is quite as 
much as you are likely to swallow at one sitting, it may be the best 
policy to conclude, thanking you for your kind attention. 
