MYLIOEATIS AQUILA. 103 



Tail flexible, very long and slender, subcompressed and slightly keeled beneath, 

 somewhat square towards the tip, which, when peifect, ends in a fine almost 

 hair-Hke point, but is usually from injury more or less oljtuse. The whole 

 resembles the thong of a coachman's whip. It originates a little within the 

 hinder margin of the wings, and its length is about twice the length of the body 

 from the tip of the muzzle to the hinder margin ; rather exceeding the width from 

 tip to tip of the wings. Quite at its base, on the upper or dorsal side, is placed 

 the small triangular dorsal fin, which is rounded at the tip, ti-uncate behind, 

 nearly twice as long as high, and does not reach quite so far as the end or tip of 

 the ventral fins, or much beyond the general outline of the hinder margin of the 

 wings. Close behind it on the tail are one or sometimes two flattened two-edged 

 straight acuminate spines, from half an inch to an inch long, with their edges 

 barbed, or retro-serrate from the point, lying flat backwards along the upper side ' 

 of the, tail ; and, though proportionately small in this fish, capable of inflicting 

 severe lacerated wounds, and rendering the fish an object of some terror to the 

 fishermen. When captured, it lashes and writhes the tail backwards and forwards ; 

 endeavouring to strike and tear with these its formidable weapons. 



The ventral fins are on each side the root of the tail, oblong, rounded or trun- 

 cate behind, and extending a little beyond the general outline of the hinder mar- 

 gin. In the males, such as the example figured, they are furnished at their inner 

 edge with a small obtuse flattened clasper, scarcely so long as themselves ; and 

 these appendages are connected with each other at the base by a skinny fold or 

 flap passing under the root of the tail. 



There are no tubercles or prickles on the tail or elsewhere in this fish ; but the 

 top of the head, with a certain space all down the middle of the back, is generally 

 in both sexes slightly rough or scabrous : the roughness, which is formed of remark- 

 ably distinct or subremote raised points, spreads a little over the base of the wings, 

 breaking irregularly into patches. The remainder of the upper surface, like the 

 whole of the under, is quite smooth. The tail is rough all round towards the 

 tip : but only so on one side or the other, above or beneath, forwarder ; becoming 

 quite smooth towards its base. 



Young male individuals are sometimes altogether smooth ; even with the tail 

 so throughout. 



Colour above an uniform greenish or olive liver-brown ; with here and there 

 some bronze or coppery tints : beneath, pure white, except towards the hinder 

 margin, which is brown. Tail dark brown. Iris rich glaucous green, clouded with 

 dark brown, forming a ring on the gi-een ground. 



The individual figured was a male, measuring two feet eight or nine 

 inches from tip to tip of the wings, and four feet five or six inches from 

 the tip of the muzzle to that of the outstretched tail : of this last quantity 

 the tail measured nearly three feet. The body was four inches thick, or 

 rather deep, just behind the head, in a line from tip to tip of the wings. 



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