42 



SALMONID^. 



Description of a Male specimen in the Orilse-state {after first return 

 from the sea), from the Uhymney. 



inches. 



Total length 14 



Greatest depth of the body 2|- 



Length of the head 2^ 



Girth of the biggest part of the body 6 



Least depth of the tail 1^ 



Girth of narrowest part of the tail 2-|- 



Distance between end of snout and eye f 



Length of maxillary bone 1^ 



Distance between eye and angle of praeoperculum , . 1 jig 



Greatest width of operculum | 



Greatest depth of operculum 1 



Distance between occiput and origin of dorsal 3|- 



Distance between end of dorsal and root of caudal ... 4|- 



Length of base of dorsal \^ 



Greatest height of dorsal 1^ 



Length of pectoral If 



Distance between root of pectoral and root of ventral 3^ 



Length of ventral fin 1| 



Distance between root of ventral and origin of anal fin 2| 



Length of anal fin \ 



Greatest depth of anal 1^ 



Length of longest caudal ray 2 



Length of middle caudal ray -i 



The greatest depth of the body is below the origin of the dorsal 

 fin, and is contained four times and three-fourths in the total length 

 (without caudal) ; the length of the head is contained four times and 

 one-third in the same. The snout is scarcely produced, conical, and 

 is one-half the length of the postorbital portion of the head ; the 

 mandible is without hook, and the jaws close perfectly ; the maxLllaiy 

 bone is longer than the snout by about one-half the diameter of the 

 eye, and extends shghtly beyond the posterior margin of the orbit, the 

 width of its broadest part being less than the diameter of the eye. 

 The mandibulary, intermaxillary, and palatine teeth are about equal 

 in size and larger than those of the maxillary. Of the vomerine teeth 

 very few remain even at this early age ; three of them are situated 

 behind the head of the vomer, and one in the middle of the length of 

 the longitudinal ridge. 



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

 the diameter of the latter ; the interorbital space is convex and some- 

 what flattened above, the orbit being situated somewhat below the 

 upper profile of the head, the width of the interorbital space is one- 

 eighth of an inch shorter than the length of the maxillary bone, and 

 one-fourth of an inch shorter than the distance between the pupil 

 and the angle of the praeoperculum. The praeoperculum has the hinder 

 margin rounded, as also the angle and lower limb, which is less per- 

 fectly distinct than in the fuU-grown fish. The posterior margin of 



