of the Parr. 27 1 



and nearly nine inches. It abounds in nearly all the Ber- 

 wickshire rivers. 



The general colour on the upper parts is a greenish-grey, 

 changing to pure silvery white on the lower parts, which, 

 however, are sometimes tinted with yellow. When the 

 streams which they frequent are impregnated with moss 

 from some of the small alpine sources, upon each side is a row 

 of oval-shaped marks of a deeper tint, and more inclining to 

 bluish-grey than that of the upper parts ; and it is probable, 

 that from a somewhat similar marking being seen in the 

 young of the common trout, and the young of several other 

 Salmonidse, the supposition of this being identical with 

 some of them was first surmised. In the parr these mark- 

 ings are narrower and more lengthened in their form. The 

 general smaller spotting of the sides seldom extends below 

 the lateral line, and upon the gill-cover there are almost 

 always two black spots ; sometimes one is only distinctly 

 marked, but a trace of the other is perceptible, and the 

 relative position of them is almost always alike. In com- 

 parison with a trout of similar size, the parr is altogether 

 more delicately formed ; the nose is blunter ; the tail more 

 forked ; but the chief external distinction is the great com- 

 parative power of the pectoral fins, which are longer, much 

 more mascular, and nearly one-third broader ; and we 

 shall at once see the necessity of this greater power, when 

 we consider that they serve to assist in almost constantly 

 suspending this little fish in the most rapid streams. Scales 

 of the parr, taken from the lateral line, were altogether 

 larger, the length greater by one-third ; the furrowing 

 more delicate, and the form of the canal not so apparent or 

 so strongly marked towards the basal end. In the osteology 

 of the head, which appears to offer the most constant and 

 well-marked distinctions in this tribe, the general delicacy 

 (still continuing the comparison with a trout of same size) 

 of the bones is in all parts kept up. The opercle, forming 

 the posterior edge of the gill-covers, is much more rounded, 

 approaching, in this respect, to the form of it in the salmon ; 

 in the trout, the lower corner is decidedly angular. The 

 inter opercle is longer and narrower. The maxillary bone is 

 much shorter, but broader at the posterior end, whence the 

 much shorter or less gape in \\u> parr. The vomer is much 



