ROUGH-TAILED STICKLEBACK. 93 



the sides defended throughout their whole length by a scries 

 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. 



Some difference of opinion appears to exist in reference to 

 this and the two or three next Sticklebacks herein described, 

 whether they ought to be considered distinct species, or only 

 varieties. I am still inclined to think them distinct, and find 

 that Dr. Parnell and Mr. Couch agree with Baron Cuvier in 

 considering them distinct. Dr. Parneirs observations will be 

 found in his essay on the Fishes of the Forth, published in 

 the seventh volume of the Memoirs of the Wernerian Society. 

 Mr. Couch, in the Cornish Fauna, says, " Having kept the 

 first and third alive in glass vessels, and finding them to ma- 

 nifest very different habits, I have no hesitation in believing 

 Mr. Yarrell to be correct in his opinion of their being speci- 

 fically distinct." 



