NATURAL HISTORY. i)3 



" The salmon, (which at spring forsakes 

 Thetis' salt waves,) to look on him, 

 Upon the water's top doth swim." SHERBURNK. 



in the females ; and the abdomen is larger in the females than in the males : the 

 males may be distinguished by their somewhat sharper and more pointed 

 head, the greater length of gill cover, and the body, from the dorsal fin downwards, 

 being not so deep compared with the whole length of the fish. 



The organs of reproduction consist of two elongated oval lobes of roe, one on 

 each side of the body, placed between the ribs and the intestinal canal ; the lobes 

 in the female called hard roe, contain a very large number of roundish ova, or 

 eggs, enclosed in a membranous bag. In the male, the lobes of roe are smaller 

 than in the females, and have the appearance of two elongated musses of fat, which 

 are called soft roe. In the spawning season, these soft rows become fluid, and are 

 voided during the time of spawning, the ova of the female being impregnated 

 thereby. 



1066. Why do salmon, when either ascending or descending 

 rivers, halt in the brackish water where fresh and salt water 

 mingle ? 



By so doing, they accustom themselves gradually to the 

 change of element which they have to undergo. And here they 

 obtain a release from numerous parasitic animals, those of the 

 salt water being destroyed by contact with fresh, and vice versa* 



1067. Why is the jlesh of the salmon red ? 



It has been assumed by Dr. Knox, that this redness is owing to 

 the peculiar food upon which the salmon subsists when at sea 

 consisting of the eggs of various kinds of small marine animals. 



Salmon are known to eat, also, sand-eels, small fishes, and various 

 diminutive marine animals. Mr. Morrison stated before the 

 Highland Society, that he had taken salmon within flood mark, 

 some of which had two, and others three, full-sized herrings in 

 their stomachs. 



1068. }V~hat circumstances give rise to the various varieties of 

 trout ? 



It is probable that there are not only varieties, but that there is 

 more than one species of river trout. But when we consider 

 geologically the various strata traversed by rivers in their course, 

 the effect these variations of soil must produce upon the water 



