30 THREE CRUISES OF THE " BLAKE." 



places it in 1,500 fathoms. Most of the specimens known have 

 been collected at the surface, and there seems to be a reasonable 

 probability that this genus inhabits intermediate depths, since 

 mid-depth fishes only have been found in its stomach. 



The gurnards have also representatives in deep water, if the 

 remarkable new genus Hypsicometes is one of its members. 

 This has been obtained both by the " Blake " and by the " Al- 

 batross " at various depths from 68 to 324 fathoms, and four 

 species of the family touch the hundred - fathom line or go 

 below it. 



The Agonidse are represented in 324 fathoms by one species 

 of Peristedium (Fig. 209), remarkable for its branching barbels, 



Fig - . 209. — Peristedium longispatha. About ^. 



and three others found between 140 and 300 fathoms, — all the 

 result of recent American explorations. 



It is worthy of note, that the characteristic abyssal families 

 are apparently offshoots of free-swimming species of active hab- 

 its, which have, in the course of time, become gradually accli- 

 mated in the depths of the sea. Their approach to great depths 

 would appear to have been in vertical lines, rather than upon 

 the slopes of the ocean bottom. 



One of the most aberrant types, Notacanthus, was obtained by 

 the " Challenger " from a depth of 1,875 fathoms. N. phasga- 

 norus was taken from the stomach of a shark killed on the 

 Grand Bank of Newfoundland. 



Many members of the group of Pediculati are often met with 

 swimming on the surface. They are species whose habits seem 

 to have become modified to those of deep-sea fishes, while they ap- 

 parently retain the characteristics of their surface allies, the most 

 familiar representatives of which are the goose-fish (Lophius) 



