100 SALMONID^. 



greatest width being less than one-half of the latter. The lower 

 jaw is without any trace of a hook, and the mouth closes perfectly. 



Teeth of moderate strength ; those on the vomer are in a single, 

 and partly zigzag, series. 



The interorbital space is flattened, with the median ridge not much 

 elevated ; the eye is immediately below the upper profile of the 

 head : the -width of this space is less than the distance from the eye 

 to the angle of the prjeoperculum, or three-fifths of the length of the 

 maxillary bone. 



The posterior margin of the prgeopereulum is rounded, the lower 

 limb being very indistinct: posterior margin of the operculum 

 straight, meeting the lower at a right angle. The distance from 

 the upper end of the gill-opening to the angle of the operculum is 

 greater than that fi'om the latter point to the lower anterior end of 

 the subopcrculum. Suboperculum thrice as long as broad. 



The distance of the origin of the dorsal fin from the occiput is 

 equal to that from the root of the last ray of that fin to the hinder 

 end of the adipose*. The dorsal fin is higher than long, and pos- 

 sesses fourteen rays, the three first of which are rudimentaiy, the 

 fourth simple, the fifth branched and the longest of the fin, and the 

 last one cleft to its base. 



The anal fin is two-thirds as long as high, and consists of twelve 

 rays, the first two of which are rudimentary, and the third simple ; 

 the fifth is the longest ray, and the terminal ray is cleft throughout. 



The pectoral fin is long, reaching more than midway between its 

 root and that of the ventral fin ; the latter fin is equal in length to 

 three-fourths of the distance of its root from the vent : its oiiter ray 

 is vertically opposite the eleventh of the dorsal fin. Caudal emar- 

 ginate, with the lobes pointed. 



There are 122 transverse series of scales, counted immediately above 

 the lateral line ; the series descending obliquely backwards from the 

 origin of the dorsal fin to that line has 28 scales ; the series descend- 

 ing obhquely forwards from the hinder end of the adipose to the 

 lateral line has 16 scales ; there are 23 longitudinal series between 

 the lateral line and the root of the ventral fin. 



Back blackish, with silvery lustre ; sides and belly greyish, each 

 scale with the centre silvery: numerous black ocelli, of a smaller 

 and larger size, and surrounded by a whitish rim, occupy the sides, 

 particularly of the trunk. Operculum with a sQvery blotch, and 

 with two or three black spots. Dorsal, ventral, and anal fins with 

 a black and white outer margin ; the first with two or three series of 

 ovate deep-black spots of moderate size. Caudal and posterior third 

 of pectoral blackish. 



* This peculiarity of the forward position of the dorsal fin is found again in 

 a second (female) example from the same locality ; however, that this is not a 

 specific character is evident from a third (male) specimen, also from Llyn Gadr, 

 in which the distance of the dorsal from the occiput is considerably more than 

 its distance from the adipose fin. 



