1. SALMO. 29 



lower jaw especially, the thickened skin on the back, and the state 

 of the sexual organs show that the specimen was engaged in, or 

 very close to the time of, spawning. The snout is so much pro- 

 duced that the posterior margin of the eye occupies the middle of 

 the length of the head, the upper profile of the head is somewhat 

 concave, the lower jaw terminates in a hook half an inch high and 

 received into a deep hole in the upper jaw. The maxillary is com- 

 paratively not very strong, not much extending behind the hinder 

 margin of the orbit. Two teeth are still on the front of the vomer. 

 Adipose fin long, broad, and extremely thick. Caudal fin trimcated. 

 Scales on the back entirely covered by the skin. There are thirteen 

 scales in a series obliquely descending from behind the adipose fin to 

 the lateral line. 



Silvery, -nith a light brownish-red tint aU over the body. Sides 

 with irregular black spots, each of the size of a scale. 



Pyloric appendages forty-three. 



Description of a Male Bull-Troutfrom the Tweed, cawjht in the month 

 of January, during the spawning -time. 



inches. 

 Total length 20 



Greatest depth of the body 4i 



Length of the head 4| 



Girth of the biggest part of the body 9| 



Least depth of the tail li 



Distance between end of snout and eye If 



Diameter of the eye X 



Length of the maxUlary bone 1| 



Distance between eye and angle of praeoperculum . . 1| 



Greatest width of operculum | 



Greatest depth of operculum 1-5 



Distance between occiput and origin of dorsal fin. . . . 6^ 



Distance between end of dorsal and root of caudal . . 7^- 



Length of base of dorsal IX 



Greatest height of dorsal li 



Length of pectoral 2\ 



Distance between root of pectoral and root of ventral 5 



Length of ventral fin 1| 



Distance between root of ventral and origin of anal . . 3| 



Length of anal is. 



Greatest depth of anal IZ 



Length of longest caudal ray 2\ 



Length of middle caudal ray 1 3 



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

 fin, and is two-ninths of the total length (without caudal), being a 

 quarter of an inch shorter than the length of the head. The snout is 

 produced, pointed, and more than half the length of the postorbital 

 portion of the head, or four-fifths of that of the maxillary bone. The 



