^^2 



Additiom io the British Fishes. 



work before mentioned ; but I send you herewith drawings of 

 the three species, of the natural size, which, I trust, you will 

 do me the favour to have engraved, the external characters 

 by which they are distinguished will be found so obvious that 

 no person need afterwards mistake them. 



The first species [Jig, 127. «), which occurs most frequently, 



is the Gasteros- 

 127 teus trachiirus 



(rough-tailed) of 

 Messrs. Cuvier 

 and Valenciennes. 

 The scales on 

 this fish extend 

 throughout the 

 whole length of 

 the side, from the 

 operculum to the 

 origin of the cau- 

 dal rays. The 

 principal dorsal 

 fin has nine rays, 

 the pectoral ten, 

 the anal seven, 

 the caudal twelve ; 

 the principal dor- 

 sal spine long, 

 blunt, ks lateral 

 serrations short 

 and few in num- 

 ber; 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 ; there are two distinct 

 rows of small teeth on the upper jaw ; on the lower jaw the 

 teeth appear irregular as to central distribution, but ending in 

 a single narrow line at each side. 



The second species (b) is the G. semiarmatus of the same 

 authors. In this fish the lateral scales extend no farther 

 backwards than the line of the vent, and slight differences 

 exist between this and trach^rus in the number of some of its 

 fin rays. Dorsal ten, pectoral ten, anal nine, caudal twelve. 

 The teeth in both jaws of this species are larger and more 

 numerous than in the trachurus, and not disposed in regular 

 rows. 



The third species {c) is the G. leiurus (smooth-tailed) of 



The line with an asterisk, descending from the abdominal edge 

 of each fish, marks the situation of the vent. 



