522 Additions to the British Fishes. 
work before mentioned ; but Isend 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 Ww ill be found so obvious that 
no person need afterwards mistake them. 
The first species (fg. 127. a), which cccurs most frequently, 
is the Gasterés- 
teus _ trachurus 
(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, its later af 
serrations short 
and few in num- 
ber; the ventral 
The line with an asterisk, descending from the abdominal edge = Le . 
of each fish, marks the situation of the vent. 4 spine tr langular 
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 (6) 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 trachirus 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. leitrus (smooth-tailed) of 
