THE OTTAWA NATURALIST 



VOL. XXII. OTTAWA, OCTOBER, 1908 No. 7. 



INFANT CANNIBALISM AMONG ANIMALS. 



By Professor Edward E. Prince, Dominion Commissioner 



OF Fisheries, Ottawa. 



In a paper which I read to the Royal Society (Sect. IV) in 

 May last I dealt with the two series of phenomena grouped 

 under the somewhat forbidding titles, polyembryony and 

 psedophagy. They may be regarded as the two opposite ex- 

 tremes of embryonic evolution and the survival of the fittest. 

 In the former (polyembryony) we find that a few eggs give 

 origin to an excessive number of young, while, in the latter, 

 very few young result from a large number of eggs. Biologists 

 have generally accepted the late Dr. W. B. Carpenter's definition 

 of an individual animal as the total product of a single ovum, 

 but our ideas of the potentialities of the egg will require revision 

 with the foregoing phenomena before us, and in my Roval 

 Society paper I ventured on some suggestions as to the signifi- 

 cance of recent observations, very curious ones, made by certain 

 biologists. Dr. Gilchrist, Dr. Sylvestri, Marchal, and others, 

 which I intend to publish with plates ere long, but in the present 

 brief article I shall deal only with paedophagy, avoiding technical 

 terms as far as possible. 



Fifty years ago Dr. Carpenter, one of the profoundest and 

 most philosophical physiologists and morphologists of the 19th 

 century, discovered that, from the numerous eggs (500 or 600 

 at least being produced by one parent each season), of that 

 common sea-shore mollusk, the dog whelk (Purpura lapillns), 

 not more than thirteen to twenty lembryos finally emerged into 

 the open water. To quote the succint description of Carl Claus, 

 "The Prosobranchs enclose their ova in capsules . attached... to 

 each other or to foreign substances. Each nidamental capsule 

 of the group shows an aperture, and contains a certain number 

 of vitelline globes or eggs, floating in clear jelly-like albumen. 

 Only a portion of these develop into embryos. One only may, 



