FISHES. 55 



Vol. I. p. 770). There are few species alone which may be regarded 

 as cosmopolitan, and then only in an improper sense, whilst they 

 occur, for example, in most seas only, but not in the North Sea, as 

 Temnodon saltator. The fishes of the Mediterranean are met with 

 in part in the North Sea also ; but many are peculiar to this 

 large lake, or spread themselves along the west-coast of North 

 Africa to the Atlantic Ocean. The Red Sea is in many respects to 

 be regarded simply as a part of the Indian Ocean, and contains 

 many genera which do not occur in the Mediterranean, and even 

 many species which extend themselves to the extreme limits 

 of the Indian Archipelago, and sometimes even to the Southern 

 Pacific. Amongst the fresh-water fishes, the numerous genus 

 C2/2:)>'inus L. especially, and the allied genus Cobiti's, are to be 

 regarded as a group of the Eastern hemisphere, of which the 

 greatest number of species occur in India, whilst only a few are 

 met with in North America and none in South America. On 

 the other hand, the Siluroids occur equally in both hemispheres 

 of the earth, although many forms are found in the Western hemi- 

 sphere alone. 



The use which man derives from the fishes is very great. 

 Many races of people live exclusively or principally on fish. 

 Salted or dried, and thus rendered fit for transmission to a distance, 

 they form an important branch of commerce for seafaring nations ; 

 they aftord us train oil, isinglass, &c. The number of fishes 

 of which the use is injurious, is only small when compared with 

 that of the edible and useful. 



The arrangement of fishes is attended with great difficulties, 

 and it seems to be rather the avoidance of what is frail than the 

 attainment of what is perfect, that the most earnest investigations 

 and the most learned disquisitions have yet to offer us. 



