352 



NATURAL HISTORY 



usually has a triangular shape, the belly being flat, and the back acute. 

 Specimens are very common in every museum and seaside town. 



Distantly related to them are the peculiar swell-fish, mostly tropical, 

 which, when captured, inflate the body with air so that another of their 

 names, balloon-fish, is very appropriate. They have not the slightest eco- 

 nomic value, but might almost seem to be constructed for the purpose of 

 serving as curiosities. Of both these and the trunk-fishes there are several 



Fig. 325. — Swell-fish, or balloon-fish (Tetrodon fahaka). 



species in the tropical seas ; some occurring occasionally as far north as 

 New England. 



As useless as it is strange, is the large sea sun-fish which is found in all 

 the northern seas, the Pacific as well as the Atlantic. Descriptive jDowers 

 fail when one attempts to picture in words this ichthyic oddity. It is all 

 head, and is chopped off square behind, where, on either side, arise the 

 dorsal and anal fins. The tail-fin bears no resemblance to the ordinarv tail 

 of fishes, but seems rather a frill to relieve the otherwise utterly absurd 

 appearance of the fish. 



In our northern waters one occasionally sees these forms basking at the 

 surface, with the dorsal-fin, like that of a shark, extending above the waves. 

 At times it would almost seem as if they were asleep in this position, as they 

 take not the slightest notice until the boat is close upon them. If one wishes 

 a drenching this is his opportunity ; for if he strike the fin, say with an oar, 



