SALMO BRACHYPOMA. 309 



that of the Brook Trout ; larger scales on the tail ; and fifty pyloric appendages, 

 instead of about forty, as in that form. 



The head is rather short, and the body somewhat slender ; the pre-oper- 

 culum has the lower limb indistinct, as in S. nigripinnis. The snout is 

 similarly short and conical. The vomerine teeth are in a single series, and 

 persistent. The pectoral fin is rounded, the caudal truncate. There are about 

 thirteen scales in a transverse series, descending obliquely forward, from behind 

 the adipose fin to the lateral line. The dorsal fin shows some black spots, and 

 the sides have more or less numerous black reticulated spots, with a few red 

 ones interspersed. 



It has fifty-six to fifty-seven vertebrae. 



Salmo polyosteus (GUNTHER). 



D. 13, A. 11, P. 14, V. 9. Scales : lat. line 128, transverse 2830. 



This species is founded upon fishes, in indifferent preservation, from Lap- 

 laud, which reach a length of about seventeen inches. 



The teeth on the body of the vomer are in pairs. There are fifteen scales 

 in an oblique series, running from behind the adipose fin to the lateral line. 

 The pre-operculum is somewhat crescent-shaped, with the lower limb indistinct. 



With the diminished number of rays in the fins there are ten branchiostegal 

 rays instead of eleven in S. venernensis, and eleven or twelve in S. mistops. 

 It is probably a variety of S. venernensis. 



Salmo brachypoma (GUNTHER). The Grey Trout. 



D. 13, A. 1011, P. 14, V. 9. Scales: lat. line 118128, transverse 27/30. 



The Grey Trout is a migratory species which frequents the rivers Forth, 

 Trent, and Ouse. It has generally been identified with the S. eriox of Lin- 

 naeus; but is distinguished by Giinther as having a comparatively small head, 

 though the head increases in length in old males, when it may be a quarter 

 of the length of the body without the caudal fin. The body is rather more 

 slender, and the maxillary bone narrower, than in S. fario. The teeth are 

 rather strong in both jaws ; but the zigzag double row on the vomer is 

 mostly lost when the fish is little more than half grown. The caudal fin is 

 truncate in individuals only ten inches long, but all the fins are small. The 

 dorsal, ventral, and anal fins have the outer margin black and white in young 

 specimens. The sides of the body show X-shaped or ocellate black spots, 

 with some red spots below the lateral line ; and there are round black spots on 

 the dorsal fin. It reaches a length of 30 inches. 



