1. SALMO. 55 



contained twice and one-fifth in the postorbital length of the head ; 

 the maxillary is longer than the snout by somewhat more than ono- 

 half the diameter of the eye, and extends about one-eighth of an inch 

 behind the vertical from the hinder margin of the orbit, the width 

 of its broadest part is one-half less than the diameter of the eye. 



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

 mandible being larger than those of the intermaxillary, which, again, 

 exceed slightly those of the maxillary and palatine bones, which 

 are about equal. The vomer has the head triangular, toothless ; a 

 series of teeth run along the middle of its body, they are arranged 

 in pairs at some distance from each other, the teeth of each pair being 

 placed one behind the other and not side by side, one being bent 

 towards the right, the other to the left ; there are four such pairs. 



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

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

 being far below the upper profile of the head, the width of this space 

 is one-eighth of an inch less than the length of the maxillary bone, 

 and a little more than four-fifths of the leygth of the space between 

 the pupil and the angle of the praeoperculum. The pra3operculum 

 has the posterior margin, angle, and lower limb much rounded, the 

 lattei being scarcely developed. The posterior margin of the ojier- 

 culum is nearly straight and placed at right angles to the lower 

 margin ; the hinder margin of the suboperculum is rounded, its angle 

 very obtuse. A line taken from the upper end of the gill-opening 

 to the angle of the operculum is longer than a line from the latter 

 point to the lower anterior angle of the suboperculum. 



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

 carried back from behind that fin, reaches to the hinder third of the 

 distance between the adipose and the root of the caudal. The dorsal 

 fin is rather longer than high, and composed of fifteen rays, the three 

 anterior ones being rudimentary and enveloped in the skin ; the 

 fourth ray is simple, and about half the length of the fifth, which is 

 also simple ; the fifth and sixth rays are equal, and the longest of 

 the fin, the sixth being the first branched ray. The last ray is cleft 

 CO the base. The anal fin is one-fourth higher than long, and corn- 

 Posed of twelve rays, the first three being rudimentary and enveloped 

 ]Ai skin„ the fourth simple, nearly as long as the fifth, which is 

 branched and the longest of the fin ; the last ray is split to the base. 



Pectoral longer than the postorbital part of the head ; ventral 

 shorter, its length being a little more than half of the distance of 

 its root from the vent, its outer ray is in the vertical from the tenth 

 of the dorsal. Posterior margin of caudal veiy slightly undulated. 



There are about 130 transv<^'rse series of scales, counted immedi- 

 ately above the lateral line ; the transverse series descencUng obliquely 

 backwards from the origin of the dorsal fin to the lateral line con- 

 tains twenty-seven scales, and there are twenty-three or twenty-four 

 longitadinal series between the lateral line and the root of the ventral. 

 The transverse series descending forwards from behind the adipose 

 fin contains fourteen scales : all the scales are obtusely rounded 

 behind. 



