ROUGH-TAILED STICKLEBACK. 79 



the vomer, palatine bones, or tongue : the gill-opening large ; 

 the fin-rays as follows . 



D. HI 9 : P. 10 : V. 1 : A. 1 + 8 : C. 12. 



The principal dorsal spine long and blunt, its lateral serra- 

 tions small and few in number ; a membrane attached to the 

 spine, by which it is depressed ; the ventral spine triangular 

 at the base, the serrations on its upper edge large and not 

 thickly set, those on the under edge small and numerous : 

 the sides defended throughout their whole length by a series 

 of elongated bony plates, arranged vertically; a small fold 

 of skin forms a horizontal crest on each side of the tail. 



The Sticklebacks are said to live but two, or at most but 

 three years ; and the males are generally to be distinguished 

 by the pink colour of their under surface, but both sexes 

 exhibit more than usual brilliancy at the season of spawning. 

 The colour of the back is green ; the cheeks, sides, and belly, 

 silvery white. The different species are of little value. 



