i 9 4i CATALOGUE OF FISHES OF TORTUGAS 303 



Family LOPHIIDAE. Anglers 



Lophius piscatorius Linnaeus. Allmouth 



Dr. Longley's field data contain records of the capture of 10 specimens, rang- 

 ing in length (not stated for 2) from 100 to 312 mm., taken south of Tortugas at 

 depths of 60 to 253 fathoms. 



The collection contains 3 specimens, 75, 1 33, and 278 mm. long. 



This is the widely distributed goosefish, or allmouth, known from both coasts 

 of the northern Atlantic, ranging southward on the American side in deep 

 water to the West Indies. S. F. H. 



Family ANTENNARIIDAE. Frogfishes 



Histrio gibba (Mitchill). Sargassum fish 



(Plate 34) 



Common in floating gulf weed; carnivorous, voracious, and peculiar in form 

 and structure. 



It liberates its eggs in a single gelatinous mass, which floats like a raft, mon- 

 strous in proportion to the size of the fish which produces it. Before its discharge 

 the egg mass lies close packed in the ovaries like a bank note tightly rolled up 

 from its two ends. 



Head large; gape enormous; oral breathing valves well developed; external 

 branchial apertures reduced to small circular openings in axils of pectorals. As a 

 result it is able to propel itself slowly through the water, without recourse to 

 ordinary swimming movements, for after the mouth has been filled, pressure on 

 the contained water causes it to stream out the gill openings with sufficient force 

 to move the fish. 



Its pertinacity in stalking prey is sometimes remarkable. One fish followed an 

 atherinid from end to end of a 2-foot tank eight times without rest before dart- 

 ing suddenly upon it and swallowing it. Usually it waits quietly for the indi- 

 vidual it sees draw near, the attack being delayed until a head-on approach of 

 the prospective victim is close. Thus it captures fishes almost as large as itself. 



In the details of their pattern the sargassum fish are highly variable. Their 

 bodies and fins are streaked and mottled with brown and yellow interspersed 

 with small round spots or thin irregular lines of white, all of the precise hues 

 which prevail in the masses of algae to which the species is practically confined. 

 The apparent size and conspicuousness of the eye is reduced, and its movement 

 hidden, by the extension of the body color to the margin of the pupil. The upper 

 surface of the tongue and the floor of the pharynx back to and including the 

 fourth branchial arch are marked with mottled brown and white simulating the 

 external pattern. Very changeable in shade, light individuals turning dark at 

 once when an attempt is made to catch them in tanks, whereas dark ones lighten 

 readily if given opportunity to come to rest in Sargassum, or become even lighter 

 in lighter-colored excelsior. W. H. L. 



