SALMONOIDE.E. 193 



Teeth small, subulate, pointed, and slightly curved, standing in a single crowded series on 

 the intermaxillaries, labials, and under jaw ; in two rows on the acutely projecting edge of the 

 palate-bones ; and in a cluster of six or seven on the anterior extremity of the vomer ; the 

 latter bone is flat and smooth posteriorly. The tongue is also smooth, but the pharyngeal 

 bones and the cartilaginous rakers of the upper branchial arch are rough : the rakers of the 

 other arches are smaller and softer. 



Gill-covers. — Preoperculum having the form of a moderately-curved and rather wide 

 crescent. Suboperculum more than half the height of the operculum, and not exceeding it in 

 length. Inferoperculum small and acute-angled. Eight gill- rays on the left side and nine 

 on the right. 



Fins.— Br. 9—8; D. 23—0; P. 15; V. 9; A. 13; C. 19f 



The dorsal contains 23 rays, which increase in succession from the first minute one : the 

 three last and longest ones exceed in height the greatest depth of the body : the commence- 

 ment of the dorsal is far forwards, or about half way between the gill-openings and ventrals, 

 and its attachment is equal to the distance between its first ray and the centre of the eye, or 

 between its last ray and the adipose fin. The adipose fin is partly behind the anal. The 

 ventrals originate a little anterior to the middle between the snout and the base of the caudal, 

 or under the eighteenth dorsal ray. Their scale-like appendages are long, thin, and pointed. 

 Anal rather small and rounded anteriorly. Caudal deeply forked. 



Intestines. — The alimentary canal, having its lining disposed in five large longitudinal 

 folds, descends from the gullet for two inches and a half, when it dilates considerably, bends 

 upwards upon itself, and terminates in a narrow pylorus : the dilated part resembles the 

 stomach of the coregonus albus, or attihawmeg, in its structure, but its coats are thinner. The 

 intestine, having very thin coats, runs in a straight line from the pylorus to the anus, being 

 exactly equal to the abdominal cavity in length. It gives origin, within three-quarters of an 

 inch of the pylorus, to eighteen caeca, and between two and three inches of its inferior part 

 are furnished with internal circular folds, or valvules conniventes. The liver is small, without 

 lobes, and there is a large spleen attached to the curvature of the stomach. The air-bladder 

 is large and communicates with the oesophagus. The fasces were black. 



On comparing the American specimen with a fine English grayling, for which I am 

 indebted to Mr. Yarrell, the following were the most obvious differences. The English fish is 

 much lighter in colour, with more lustre, and exhibits about sixteen faint longitudinal bands 

 passing through the centres of the same number of rows of scales. Its body is thicker, its head 

 larger, and the distance between the orbit and end of the snout measures double to what it 

 does in Back's grayling. The tubular ridges on its head are less conspicuous, and its mouth 

 is wider ; but its under jaw does not not project so far as in the latter. It also presents a 

 remarkable difference in the want of palatine-teeth, these bones being quite smooth and 

 rounded on the edge. The teeth on the mandibles are smaller than in the American gray- 

 ling, and those on the Vomer are perceptible only by the aid of a lens. Both have teeth on 

 the pharyngeal bones and rakers. There are 81 scales on the lateral line of the English 



2c 



