356 COTTID^E. 



Dimensions. 



Total length of fisli, caudal included ..... 5'60 inches. 



Length from symphysis of premaxillaries to upper angle ~) 



,, . n . ( 1'50 



oi gill-opening ............ ) 



Length from symphysis to tip of great preopercular spine T20 



Length from symphysis to anus ........ 2'51 



Length of pectorals ....... . . 1'50 



Length of ventrals ....... I'lO 



Lenth of caudal ...... 





GASTEROSTEUS INSCULPTUS. 



(An varietas, an species propria T) 



Radii: Br. 3-3 ; D. 1/-1/-1/9 ; A. 1/8 ; C. 12|; P. 11 ; V. 1/1-1/1. 

 PLATE XXV., fig. 1, nat. size; fig. 2 and 3, magnified. 



The three-spined Sticklebacks are generally spread over the 

 northern hemisphere, being inhabitants of both the fresh and 

 salt waters. On a cursory inspection it might appear to be a 

 single species that is thus widely distributed, so well is the 

 general aspect preserved in even distant localities ; but Cuvier 

 has named several forms as distinct, separating first one in 

 which the posterior side scales are deficient, and secondly an- 

 other with shorter spines. He has also described as peculiar 

 two American species, which differ but slightly from their Eu- 

 ropean representatives, and a minute comparison of specimens 

 taken in places much less remote from each other, might dis- 

 cover differences sufficient greatly to multiply these species or 

 varieties. Sir Edward Belcher has brought home a single spe- 

 cimen of that form, which possesses the complete number of 

 side-plates and dorsal spines of the usual length, but which 

 has a decidedly deeper body than its English representative : 

 he obtained it in deep water in Northumberland Sound, at a 

 distance from any fresh-water streams. 



Description. 



Having through the kindness of Dr. Baikie procured seven or 

 eight three-spined Gasterostei from the Orkneys, some of them 

 even larger than the Northumberland Sound one, I selected 



