354 



SPIJSTl '-FIXXED GR O UP, 



a considerable number of both living and extinct genera, are all marine fishes, 

 with a practical^ cosmopolitan distribution ; many of them living at great depths, 

 and coming under the denomination of deep-sea fishes. They are also a geologically 

 ancient group, represented by a large number of generic types, both existing and 

 extinct in the Chalk and other Cretaceous deposits. The only existing forms that 

 frequent the higher strata of the ocean belong to the genera Holocentrwm and 

 Myripristis; but even some species of the latter may descend as deep as one 

 hundred and fifty fathoms. The typical genus Beryx has been taken from between 

 three and four hundred fathoms ; and from the small size of the eye the forms 



GROUP OF SPINE-FINNED FISHES. 



Teuthis (upper figure) ; Pewip/im's (on the right) ; and Polynemus (on the left), (i nat. size.) 



known as Melamphcees must, in Dr. Gunther's opinion, inhabit still lower levels. 

 Another sign of their deep-water habits is afforded by the high development of the 

 slime-secreting apparatus of these fishes. 



Of the genera that space permits of our noticing, the most peculiar is 

 Monocentris, represented b} 7 a single small and rare species from the seas of Japan 

 and Mauritius, and distinguished by the absence of armatures on the gill-cover, the 

 large size of the scales, which are articulated together so as to form a solid 

 armour, and the reduction of the ventral fins to a single long spine, and a few 

 rudimental rays. The fish figured in our illustration (Trachichthys trailli) 

 represents a genus, with a few species from New Zealand and Madeira, characterised 

 by the short and blunt muzzle, the prominent chin, the strong spine at the angle 



