1. SALMO. 137 



little more than one-halt' of the width of the interorbital space. The 

 latter is convex, with a prominent ridge along the middle, and with a 

 pair of series of pores. Snout slightly compressed, subconical, wath 

 jaws equal anteriorly. The nostrils are situated midway between the 

 end of the snout and the anterior margin of the eyeball ; the posterior 

 is the wider and round, the anterior being a very narrow vertical slit ; 

 the two are separated by a narrow cutaneous bridge. The maxillary 

 extends to the vertical from the posterior margin of the eye, and is 

 armed with sixteen very small teeth, the posterior ones being quite 

 rudimentary. All the other teeth small ; four in the intermaxillary, 

 twelve in each mandible, two to foiir on the vomer, fifteen on each 

 palatine, and four pairs on the tongue. The sidjoperculum forms the 

 hindmost part of the giU-cover, and does not cover the exposed por- 

 tion of the humerus above the root of the pectoral ; it is narrow, its 

 vertical width being one-third of that of the operculum. Only the 

 two or three outer hranchiostegals are exposed in a lateral view of 

 the fish, the others being situated at the lower side of the head. The 

 lower branch of the outer hranddal arch is provided with nine lanceo- 

 late straight giU-rakers ; the longest is two lines long in the specimen 

 described. 



The origin of the dorsal fin is nearer to the end of the snout than 

 to the root of the caudal ; the length of its base is considerably more 

 than that of the last ray, and contained once and two-fifths in that 

 of the fourth ray. The fourth and fifth rays form an acute point, 

 and the upper margin of the fin is nearly straight. The fii'st ray is 

 nearly half as long as the second, the second half as long as the 

 third, the third not much shorter than the fourth ; the fourth and 

 fifth are longest, the former simple and the latter branched ; the last 

 is split to the base, and nearly half as long as the fifth. The dis- 

 tance of the adipose fin from the dorsal is less than twice the length 

 of the base of the latter. 



The origin of the anal fin is in the middle between the root of the 

 caudal and that of the outer ventral ray ; the length of its base is 

 less than that of the dorsal, and two-thirds of the length of the fifth 

 ray. The fourth, fifth, and sixth rays are the longest, and form an 

 acute point ; the lower margin of the fin is slightly emarginate. The 

 first ray is short, half as long as the second ; the second half as long 

 as the third ; the third two-thirds as long as the fourth, which is 

 simple ; the fifth branched ; the last is split to the base, two-fifths 

 as long as the fourth. 



Caudal fin forked, one of the middle rays not being quite haK as 

 long as the outer ones, the length of which is one-fifth of the total. 

 Lobes pointed. 



The base of the pectoral is entirely free, and not overlapped by the 

 gill-cover apparatus. It is as long as, or even longer than, the head, 

 and extends to, or slightly beyond, the vertical from the origin of 

 the dorsal, terminating at a short distance from the ventral. 



The ventral is inserted below the ninth, tenth, and eleventh 

 dorsal rays, its length being three-quarters of that of the pectoral ; 

 it terminates at no great distance from the vent. In smaller speci- 



