CiiAP. XIX. 



Fishes. 



333 



Salmo hjcaodon of N.-W. America the change, as Mr. J. K. Lord 8 

 believes, is permanent, and best marked in the older males which 

 have previously ascended the rivers. In these old males the 

 jaw becomes developed into an immense hook-like projection, and 



Fig. 27. Head of male common salmon (Salmo salarl during the breeding-season. 



[This drawing, as well as all the others in the present chapter, have been executed 

 by the well-known artist, Mr. G. Ford, from specimens in the British Museum, under 

 the kind superintendence of Dr. Gunther.] 



the teeth grow into regular fangs, often more than half an inch 

 in length. With the European salmon, according to Mr. Lloyd, 9 

 the temporary hook-like structure serves to strengthen and 



8 ' The Naturalist in Vancouver's 9 ' Scandinavian Adventures,' vol 



bland,' vol. i. 1866, p. 54. i, 1854, pp. 100, 104. 



