118 



ARGUS PTERACLIS. 



Pteraclis ocellatus^ Cuv. & Vau 



PLATE X. 



These fishes have more than double the expanse of 

 their surface in the dorsal and ventral fins, and one 

 is at a loss to perceive for what purpose this im- 

 mense developement is necessary ; at the same time, 

 we must confess our entire ignorance of their habits 

 and economy. It had been supposed that they 

 were enabled to support themselves for a short 

 period in the air, but this is not confirmed by any 

 observations; and we do not see how such could 

 take place in the perpendicular position of the fish. 

 Two or three species only are known, and oiu: pre- 

 sent one is of extreme rarity. Mons. Cuvier and 

 Valenciennes took their specimen from the stomach 

 of another fish. It was procured on the Mozam- 

 bique coast. 



In the Histiophori or sword-fishes, where the 

 passage through the water is extremely rapid, and 

 which possess great strength, the dorsal fin is very 

 large. So is it also in another curious fish, a 

 native of the Madeira seas — Alepisaurus ferox. In 



