CHAPTEE XIX. 



THE DISTEIBUTION OF MARINE FISHES. 



Maeine fishes fall, with regard to their mode of life and dis- 

 tribution, into three distinct categories : — 



1. Slwre Fishes — That is, fishes which inhabit chiefly 

 parts of the sea in the immediate neighbourhood of land 

 either actually raised above, or at least but little submerged 

 below, the surface of the water. They do not descend to 

 any great depth,— very few to 300 fathoms, and the majority 

 live close to the surface. The distribution of these fishes is 

 determined not only by the temperature of the surface water 

 but also by the nature of the adjacent land, and its animal 

 and vegetable products ; some of these fishes being confined 

 to flat coasts with soft or sandy bottoms, others to rocky and 

 fissured coasts, others to living coral formations. If it were 

 not for the frequent mechanical and involuntary removals to 

 which these fishes are exposed, their distribution within cer- 

 tain limits, as it no doubt originally existed, would resemble 

 still more that of freshwater fishes than we find it actually 

 does at the present period. 



2. Pelagic Fishes — that is, fishes which inhabit the sur- 

 face and uppermost strata of the open ocean, which approach 

 the shores only accidentally, or occasionally (in search of 

 prey), or periodically (for the purpose of spawning). The 

 majority spawn in the open sea, their ova and young being 

 always found at great distance from the shore. With regard 

 to their distribution, they are still subject to the influences of 

 light and the temperature of the surface water ; but they are 



