348 PISCES (OSSEI) ACANTHOPT. [GASTEROSTEUS, 



This species, the Perca marina of Linnaeus, frequents high latitudes, 

 and is little known as a native of our own seas, excepting along the 

 northern coasts of the Island. Has been met with on the coasts of Aber- 

 deenshire and Berwickshire; also in Zetland by Dr. Fleming. Food, 

 according to Cuvier, Crustacea and small fish. Obs. It is very doubtful 

 whether the Sea-Perch of Willughby * be referable to this species. 



GEN. 8. GASTEROSTEUS, Linn. 



(1. GASTEROSTEUS, Cuv.) 

 * Sides more or less protected by transverse scaly plates. 



22. G. aculeatus, Linn. (Three-spined Stickleback.) 

 Three dorsal spines. 



G. aculeatus, Linn. Syst. Nat. torn. i. p. 489. Block, Ichth. pi. 53. 

 f. 3. Don. Brit. Fish. vol. i. pi. 11. Flem. Brit. An. p. 219. 

 G. trachurus, leiurus, & semiarmatus, Cuv. et Vol. Pom. torn. iv. 

 p. 352. pi. 98, & p. 361. G. trachurus, & gymnurus, Cuv. Reg. An. 

 torn. ii. p. 170. Stickleback, Will. Hist. Pise. p. 341. tab. X. 14. 

 f. 1. Bowd. Brit.fr. wat. Fish. Draw. 20. Three-spined Stickle- 

 back, Penn. Brit. Zool. vol. HI. p. 261. pi. 50. no. 129. Id. (Edit. 

 1812.) vol.111, p. 353. pi. 61. 



LENGTH. From two to two and a half, rarely three inches. 



DESCRIPT. (Form.) Oval; rather elongated; sides compressed; tail 

 slender ; dorsal and ventral lines equally convex : greatest depth about 

 the middle, rather more than one-fifth of the entire length ; head one- 

 fourth ; thickness a little more than half the depth : eyes large : cranium 

 more or less striated, the striae formed of minute granulations : mouth 

 protractile; when closed, the lower jaw advancing a little beyond the 

 upper: both jaws with fine small teeth, but none on the tongue, vomer, 

 or palatines : opercle large and triangular, the posterior margin rounded : 

 no true scales, but the sides protected by a series of oblong osseous plates, 

 varying in number, disposed in transverse bands ; a similar plate, ascend- 

 ing from the base of the ventrals, reposes on the third and fourth of the 

 above series ; there is also another placed longitudinally on each side of 

 the breast, and a large triangular one on the belly, having its base in a 

 line with the ventrals, and its apex directed towards the vent ; all these 

 scaly plates more or less granulated in lines : instead of a first dorsal 

 three free strong spines, a little distant from each other, more or less ser- 

 rated at their edges, varying in length, but the second always longest ; 

 first spine above the first or second of the lateral scaly plates ; second 

 above the fourth ; the third, which is much smaller than the other two, 

 in a line with the apex of the triangular plate on the belly : soft dorsal 

 commencing immediately behind this last spine ; all the rays, except the 

 first, branched : anal about half the length of the soft dorsal, with one 

 short, curved, free spine immediately before the first ray : caudal rounded : 

 ventrals consisting of one strong serrated spine, united by a delicate mem- 

 brane to one slender soft ray scarcely one-third of its own length : 



D. 310 to 13; A. 1/8 to 10; C. 12 ; P. 10; V. 1/1: 



sides of the tail sometimes furnished with a horizontal expansion of 

 the skin forming a keel. Number of vertebrae thirty-three. (Colours.} 



* Hist Pise. p. 327- 



