3o6 THE GREAT BARRIER REEF. 



or other special features. The sucking-fish, Echencis naucrates, delineated by Figs, ia and b 

 of Plate XLV., represents one of the aberrant members of the mackerel tribe, or Scombridae, 

 remarkable for the adhesive disk on the top of its head. This structure is a modified derivative of 

 tiie anterior dorsal fin, consisting of a double series of cutaneous lamellae which, on being erected 

 at will, produce, in conjunction with the external membranous border, a perfect vacuum. With 

 this adhesive organ the sucking-fishes are in the habit of attaching themselves to sharks, turtles, 

 and sailing vessels, utilising the selected object, in either instance, merely as a means of 

 locomotion. The species here figured grows to a length of three feet, and, as related in the 

 succeeding chapter, is employed by the natives of Torres Strait for the capture of turtle. 



Two large species of fish belonging to the shark tribe, possessing no marketable value, not 

 hitherto referred to, are included in Plate XLVIII. One of these. Figs. 2 and 3, known as the horned- 

 or ox-ray, Diccrobafis ercgoodoo, Cuv., is remarkable for the enormous size to which it may attain. 

 In Queensland waters, in the neighbourhood of the Palm Islands, a specimen has been captured 

 measuring twelve feet across the expanded fins, and others of nearly equal dimensions have been 

 reported to the author from various localities in the Barrier district. On the Indian coast, 

 however, specimens have been captured measuring over eighteen feet in width. This Oriental 

 ray appears to be perfectly harmless, but there are two allied species — Dicerobatis giorncc, 

 of the Mediterranean, and Ceratoptera vampyrus, of the Carribbean seas — locally known in the 

 former instance as the Vacca or Sea-cow, and in the latter as the Devil-fish — that possess the evil 

 reputation of attacking divers when engaged in collecting sponges and pearl-shell, intercepting 

 their attempts to regain the surface. 



The Queensland species, from its habit of basking on the surface of the water, is popularly 

 known as the sun-fish. It has been reported to the author by Captain Thomson, the very obser- 

 vant commander of the A. U.S.N. Co.'s steamer Quirang, that this fish, impelled apparently with 

 the desire of evading some enem}', will spring out of the water to a height of at least twenty 

 feet. The ox-ray, as will be recognised by its form, is very nearly allied to the sting-rays of 

 the genus Trygon and Myliobatis, but differs from them in being devoid of a caudal spine, 

 and in the peculiar horn-like prolongation of the anterior edge of the pectoral fins. The 

 teeth in the members of this genus are relativel}' minute and weak, and not modified, as in the 

 case of the sting-rays, Trygon, for crushing hard shell-fish and Crustacea. This circumstance and 

 its floating habits, appear to indicate that it is a surface feeder, feeding upon the vast shoals 

 of larvae and other organisms that swarm on the upper stratum of the tropical seas in calm 

 weather. It has furthermore been observed of examples floating on the surface of the water, that 

 the horn-like appendages, which are exceedingly flexible in life, are frequently inflexed towards 

 the mouth, as though sweeping in the water with its suspended contents. The extreme width of 

 the mouth, discernible in the accompanying illustration (Fig. 2), which opens disclosing a cavity 

 like a carpet-bag, and the wonderfully complex modification of the gill arches, which un- 



