LONG-TAILS AND FLAT-FISHES. 



439 



of life, frequently swimming near the surface in large shoals, when they will at 

 times suddenly descend to the bottom, where they bury themselves with surpris- 

 ing rapidity by the aid of the elongated horn-like extremity of the elongated lower 

 ijaw. During ebb-tide, numbers remain buried at the depth of five or six inches in 



LESSER SAND-EEL (f nat. size). 



the sand till the next flood ; and it is then that they are dug out with rakes or 

 other implements. When swimming, they are followed by shoals of mackerel 

 and porpoises. 



The last group of the family is represented by Conyrodus of the 

 Australian coasts, and Haliophis from the Red Sea, both of which 

 differ from the sand-eels by the narrower gill-openings, and the union of the two 

 gill-membranes beneath the throat. 



Conyrodus. 



THE LONG-TAILS, Family MACRUEID^E. 



The fourth family of the symmetrically formed soft-finned fishes is typically 

 represented by the genus Macrurus, as well as by several allied forms. These fish 

 are characterised by the body ending in a long, compressed, and tapering tail, covered 

 with spiny, keeled, or striated scales, and unprovided with an expanded fin. There 

 is a separate short first dorsal fin, followed, after a short interval, by a very long 

 and low second dorsal, which is composed of very weak rays, and is continued to 

 the end of the tail ; the anal occupying a precisely similar position on the under 

 surface, and the thoracic or jugular pelvic fins consisting of several rays. Dr. 

 Giinther writes that " this family, known a few years ago from a limited number 

 of examples, representing a few species only, proves to be one which is distributed 

 over all oceans, occurring in considerable variety and great abundance at depths of 

 from one hundred and twenty to two thousand six hundred fathoms. They are, in 

 fact, deep-sea gadoids, much resembling each other in the general shape of the body, 

 but differing in the form of the snout, and in the structure of their scales. About 

 forty species are known, many of which attain a length of 3 feet." 



THE FLAT-FISHES, Family PLEURONECTID^. 



Distinguished by the unsymmetrical conformation of the head and anterior 

 region of the body in the adult, in consequence of which both eyes are brought on 



