1. SALMO. 17 



which, again, are larger than the maxillary and palatine teeth : of 

 the vomerine teeth only two of the anterior ones are left. 



The distance of the nostrils from the orbit is nearly equal to the 

 diameter of the latter : the intcrorbital space is very convex, the 

 orbit being far below the upper profile of the head ; its width equals 

 the length of the maxillary bone or the distance between the pupil 

 and the angle of the prajoperculum. The posterior margin of the 

 operculum and suboperculum is subsemicircular ; when we fix tliree 

 points on this curved line, viz. the upper end of the giU-opening, 

 the junction of the operculum and suboperculum, and the lower end 

 of the subopercidum, and when we connect these three points by 

 two cords, the two straight lines are nearly equal. 



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

 almost equal to its distance from the adipose fin. It is rather longer 

 than high, and composed of thii'teen rays, the two anterior ones 

 being rudimentary and enveloped in skin, whilst the third is simple, 

 and nearly as long as the foiirth, which is branched and the 

 longest ray of the fin. The anal fin is higher than long, and com- 

 posed of eleven rays, the two anterior ones being rudimentary and 

 liidden in thick skin, whilst both the thii-d and fourth rays are 

 branched, and the longest : the last is split to its base. Pectoral 

 fin nearly as long as the head without snout ; ventral fin shorter, 

 its length being one half of the distance of its root from the vent ; 

 its outer ray is in the vertical from the middle of the dorsal fin. 

 Posterior margin of the caudal fin truncated. 



There are 120 transverse series of scales, counted immediately 

 above the lateral line : the transverse series descending obliquely 

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

 tains twenty-five scales, and there are twenty longitudinal series of 

 scales between the lateral line and the base of the ventral. 



The lateral and lower parts are uniform silvery. The back is 

 sparingly covered with black spots, which are limited to the mem- 

 brane between the scales, none of them being larger than a scale. 

 A single round black spot on the operculum. Fins immaculate. 



Description of a Male Irish Salmon, caught in the month of November, 

 during the Sjjaiuning- season, 36| inches long. 



inches. 



Total length 36| 



Greatest depth of the body 8| 



Length of the head 9^ 



Girth of the biggest part of the body 19 



Least depth of the tail 2i 



Girth of the narrowest part of the tail 7 



Distance between the end of the snout and the eye . . 4| 



Length of the maxillary bone 3^ 



Distance between the eye and the angle of the 



prffioperculum 3 



VOL. VI. c 



