1. SALMO. 39 



The snout is produced, pointed, and is contained once and one half in 

 the postorbital portion of the head ; the mandible has a small hook, 

 about one line in height, but the jaws can be almost perfectly closed ; 

 the maxillary bone is longer than the snout by about half the dia- 

 meter of the eye, and extends beyond the posterior margin of the 

 orbit; the width of its broadest part is less than the diameter of 

 the eye. 



The dentition of the jaws and palate is perfect, the mandibular, 

 intermaxillary and palatine teeth being equal and larger than those 

 of the maxillary. Of the vomerine teeth only three remain, which 

 are situated behind the head of the vomer. The head of the vomer 

 is triangular, broader than long, and the body of the bone has a 

 slight transverse ridge where it joins the head. 



The distance of the nostrils from the orbit is about two-thirds of 

 the diameter of the latter ; the interorbital space is very convex, 

 but somewhat flattened above, the orbit situated far below the upper 

 profile of the head ; the width of the interorbital space is three- 

 eighths of an inch shorter than the maxillary bone, and one quarter 

 of an inch shorter than the distance between the pupil and the angle 

 of the praeoperculum. 



The praeoperculum has the posterior margin subvertical, slightly 

 undulated, the angle and lower margin rounded, the latter being 

 perfectly distinct. The greater part of the posterior margin of the 

 operculum is straight, and placed at a right angle to its lower margin, 

 the angle of the suboperculum being much rounded. A line taken 

 from the upper end of the gill-opening to the posteriox angle of the 

 operculum is one-half longer than one from that point to the lower 

 anterior angle of the suboperculum. Suboperculum very narrow, 

 more than thrice as long as deep. 



The distance of the origin of the dorsal fin from the occiput, if 

 carried backwards from behind that fin. reaches a little beyond- the 

 adipose The dorsal fin is a little longer than high, and composed 

 of fourteen rays, the three anterior ones being rudimentary and 

 enveloped in skin, whilst the fourth is simple, much shorter than 

 the fifth and sixth, which are branched and the longest of the fin. 

 The last ray is cleft to the base. 



The length of the anal fin is two-thirds of its height, and the fin is 

 composed of eleven rays, of which the first and second are rudimentaiy 

 and enveloped in the skin, the third simple, shorter than the fourth 

 and fifth, which are branched, equal, and the longest of the fin. The 

 last ray is cleft to the base. 



Pectoral fin longer than the postorbital portion of the head by 

 one-half the diameter of the eye: ventral fin shorter, its length 

 being equal to somewhat more than half the distance of its root from 

 the vent ; its outer ray is in the vertical from the tenth of the 

 dorsal. Posterior margin of the caudal fin truncated. 



There are 117 transverse series of scales, counted immediately 

 above the lateral line ; the transverse series descending obliquely 

 backwards from the origin of the dorsal to the lateral line contains 

 twenty-seven or twenty-eight scales, and there are twenty longi- 



