Prince. — Inimical Animals and Conditions 65 



sues osmotically, to any large extent. Most of the dis- 

 solved food, digested intra-cellularly, appears to be re- 

 turned to the alimentary system and carried by the 

 gastro-vascular canals to remoter parts. 



I cannot, however, go into details as to the anatomy 

 and physiology and the minute histology of this interest- 

 ing phenomenon of the digestion of small Teleosteans as 

 observed by me in the jellyfish. I am publishing else- 

 where an elaborate paper on that subject. All that is 

 necessary here is to state that the destruction of young 

 fish in the sea by medusae has been demonstrated, that 

 the fish seem to be seized tail first by the prehensile 

 manubrium, masticated in the gastric chamber and dis- 

 solved by gastric solvents while the pulsations of the 

 b^l-like or umbrella-shaped medusa, driving it through 

 the water, produce a squeezing and sucking effect most 

 effectively macerating even a large object like a fish half 

 an inch long. The circulation due to cilia in the gastro- 

 vascular canals, the digestive ferments, and intra-cellu- 

 lar digestion, complete the nutritive process, whose finely 

 ground and digested elements are carried to the most dis- 

 tant parts of the bell-like body. 



Truly the enemies of young fish are legion in the sur- 

 face waters of the sea, but Nature has made ample com- 

 pensation by rendering our most valuable food fishes the 

 most wondrously prolific of all vertebrates. 



DISCUSSION. 



President: This is a world of tooth and fang and sharp claw, 

 where things eat and get eaten. Professor Prince has presented this 

 subject in a striking way and it will suggest to us all that the impor- 

 tance of these lower organisms in fish life may be much greater than 

 we have hitherto supposed. Enormous nniiilKrs of fish eggs do certainly 

 disappear somewhere, for some of these fishes produce them by the 

 million. In a few cases, I have been able to observe their seizure by 

 small organisms, l)ut the evidence is difficult to obtain, and proofs of 

 such seizure are rare. 



Dk. Huntsman, of Ontario: A year ago I started to study wall-eyed 

 pike, keeping them in quantity, and they began to eat one another. In 

 all cases the captured fish was taken tail first and the captor swam 

 about with the head of his prey protruding. One fish was captured 

 at our biological station with three heads protruding from its mouth. 

 With the perch, too, it was found that specimens from four to six 

 inches long had often swallowed others of the same species and in 



