IG SALMONID^. 



species known to us. The following descriptions will be of use for 

 comparison of specimens of a certain size and state of development. 



Description of a Male Salmon from the Tweed, 46 inches long, 



inches. 



Total length 46 



Greatest depth of the body 11| 



Length of the head 10| 



Girth of the biggest part of the body 28 



Least depth of the tail 3^ 



Girth of the narrowest part of the tail 10 



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 



prseoperculum 3^ 



Greatest width of the operculum 2i 



Greatest depth of the operculum 3 



Distance between the occiput and the origin of the 



dorsal fin .^ 14 



Distance between the end of the dorsal arid the root 



of the caudal fin 15 



Length of the base of the dorsal 4|- 



Greatest height of the dorsal 4| 



Length of the pectoral 5| 



Distance between the root of the pectoral and the 



root of the ventral 12| 



Length of the ventral fin 4^ 



Distance between the root of the ventral and the 



origin of the anal 10| 



Length of the anal 3|- 



Greatest depth of the anal 4| 



Length of the longest caudal ray 6 



The specimen is in the most perfect condition ; the scales are not 

 sunk into the skin, but perfectly and regularly imbricate, although 

 the greater portion of each of the dorsal scales is covered by the 

 basal membrane. The greatest depth of the body is below the 

 origin of the dorsal fin, and a Httle more than two-sevenths of the 

 total length (the caudal fin not included) ; the length of the head is 

 one-fourth of the same. The snout is produced, but its length is 

 somewhat less than that of the post-orbital portion of the head ; 

 the hook of the lower jaw is moderately developed, its cartilaginous 

 point being only one-third of an inch in length ; however, it pre- 

 vents the mouth from being shut, and the finger can easily pass 

 between the jaws when closed ; the maxillary bone is considerably 

 shorter than the snout, and extends scarcely beyond the vertical line 

 from the posterior margin of the orbit, the width of its broadest 

 part is less than the diameter of the eye. The dentition of the 

 jaws and of the palatine bones is almost perfect, the teeth of the 

 intermaxillary being rather stronger than those of the mandible, 



