THE SPAWNING-GROUND. 99 



The above illustration represents three pair of salmon in 

 the spawning season. It must be borne in mind, however, 

 that though three pair are depicted in their spawning-beds, 

 it is only to save other illustrations ; for it seldom happens 

 that more than one pair of fish, as regards the Save at least, 

 occupy the breadth of the stream. 



The pair to the left the female passive, the male casting 

 a jealous glance at an interloper. Second pair in the centre 

 the female on her side, in the act of distributing her ova, 

 the male passive, and the fry revelling in the passing cloud. 

 Third pair to the right the female passive, the male seizing 

 a poacher on his manor, in which interval it will be observed 

 an intruder takes advantage of the liege lord's absence, and is 

 about assuming his place. The zig-zag lines represent the 

 manner in which the milt of the male salmon, according 

 to his peregrinations, becomes distributed over the whole 

 river. 



As is well known, the jaws of the male salmon during the 

 breeding season are much elongated by the growth of a car- 

 tilaginous projection from the extremity of each. That on 

 the lower turns upwards, and when the jaws are closed occu- 

 pies a deep cavity or socket between the intermaxillary bones 

 of the upper jaw. 



The anatomical construction of these extraordinary elonga- 

 tions is curious. The lateral longitudinal surface of the hook 

 on the lower jaw is greater than that in front, thereby giving 

 it more strength, and at the same time offering less obstruc- 

 tion to the flow of the water into the gills or lungs, during 

 respiration. And from the hook inclining backwards at the 

 top, it beautifully facilitates this end. 



The upper snout is hollow or vaulted. This cavity would 



H 2 



