SYNOPSIS. 355 



C. U.Cuv. $ Vol., iv. p. 327, pi. 87 ; Tarr. Brit. Fiih., 

 i. p. 87. Perca marina, Linn.) Penn. Brit. Zool., iii. p. 349, 

 pi. 59. Scorpsena Norvegica, Northern Sebastes, Jenyn^ 

 Brit. Vert., p. 347. 



GEN. XIII. GASTEROSTEUS. Head smooth ; one dorsal fin, 

 the place of the first dorsal being occupied with from three to 

 fifteen spines ; ventral fin reduced to a single spiniform ray : 

 body without scales, the sides protected by transverse plates, 

 abdomen likewise defended by a triangular plate ; teeth in both 

 jaws, none on the vomer or palatines. 



Sp. 26. G. trachurus. Rough-tailed Three-spined Stickle- 

 back. Dorsal spines three, the central one longest ; lateral 

 plates extending to the base of the tail ; ventral spine tri- 

 angular at the base ; tail with a slight ridge on each side- 

 Fin-rays, D. iii 9 : P. 10 : V. 1 : A. 1 + 8 : C. 12. Cm\ 

 # Val., iv. p. 481, pi. 98, fig. 1 ; Tarr. Brit. Fish., \. 90. 

 G aculeatus, Don. Brit. Fish., pi. 1 1. Three-spined Stickle- 

 back, Jenyns* Brit. Vert., p. 348. 



Sp. 27. G. semiarmatus. Half-armed Stickleback. Dorsal 

 spines three, lateral plates not extending beyond the line 

 of the vent. Fin-rays, D. iii+ 10 : P. 10 : A. 1 + 9 : C. 12. 

 Cuv. & Val., iv. p. 493 ; Tarr. Brit. Fish., i. 94. 

 Sp. 28. G. leiurus. Smooth-tailed Stickleback. Dorsal spines 

 as in the two last species ; lateral plates not extending 

 beyond the second dorsal spine, the side beyond that 

 smooth and soft. Fin-rays, D. iii. + 1 : P. 1 1 : A. 1 + 8 : 

 C. 12. Cuv. & Val., iv. p. 481, pi. 98, fig. 4 ; Tarr. Brit. 

 Fish., i. 95. 



Sp. 29. G. brachycentrus. Short-spined Stickleback. Lateral 

 plates as in G. leiurus; dorsal spines three, very short. 

 Fin-rays, D. iii + 13 : P. 10 : A. 1 + 9 : C. 12. Cuv. $ 

 Val, iv. p. 499, pi. 98, fig. 2. 



Superior in size to L. leiwus, and the vertebrae more 

 numerous. 



Sp. 30. G. spinulosus. Four-spined Stickleback. Dorsal spines 

 four; a single lateral plate behind the pectoral fin. Fin- 

 rays, D. iv+8 : P. 9 : V. 1 : A. 1 + 8 : C. 12. Tarr, 



