1'8 ON TAETATlONS MT FOEM IN SALMO rONTINALIS. 



the external form and colour. At la.st, in June this year I re- 

 ceived from Sir Pryse Pryse an undoubted hybrid ; its total length 

 was 9 inches. The fish is now on the table. 



B. X. D. 14(i). P. 14. V. (right) 9, (left) 8. A. 11 (g-). 



C. 19. L. 1. iTg. L.tr. 27/39. 

 leo 



Length of head 5, of caudal fin 5j^, height of body 5 in the 



total length. JSi/e — diameter one fifth of the length of the head, 



1| diameter from the end of the snout and 1| apart. Posterior 



edge of the preopercle somewhat angular at its centre, and again 



where it commences to form its lower limb, wduch is distinct. 



"Width of operele equal to two thirds of its height. Height of sub- 



opercle at its base 2| in that of the operele, and having a rounded 



posterior edge. Teeth — 2 at the anterior portion of the body 



of the vomer where it joins the palatine arch ; 6 more along 



the body of the bone, the anterior 4 in alternate rows, the last 



2 single and the most posterior one the largest. Fins — dorsal 



commences midw^ay betAveen the end of the snout and the base of 



the caudal, which latter fin is forked. Scales — 119 rows along 



the lateral line ; 29 from the lateral line to the base of the 



ventral fin ; 19 rows in an oblique line from the posterior end of 



the base of the adipose dorsal downwards and forwards to the 



lateral line. Pish sterile : this of course may be temporary ; but 



examples of a similar and even smaller size from Howietoun had 



the ova and milt w^ell developed. Colours — those of fluviatile 



Salmo fontinalis, being grey rivulated with broad serpentine 



bands of yellowish white, or forming rings enclosing grey 



blotches which have a light centre. A few red spots along the 



lateral line, but none apparent above or below it. Dorsal, caudal, 



and ventral fi^ns coloured similarly to S. fontinalis ; but the black 



band to the anal at the base of the white outer edge not so 



distinct. 



Plere, as show^n by the scaling and dentition, was an undoubted 



hybrid between the American charr and the common brook-trout ; 



but it was sterile. It would be exceedingly interesting were a 



close scrutiny to be kept on any of these fish captured in a wild 



state, in order to ascertain when hybrids are present, and also to 



be clear as to wdiether such are sterile or the reverse. Until 



more examples have been obtained, I do not propose offering any 



opinion upon the foregoing interesting specimens, but merely to 



record facts. Sir J. Gibson-^Maitland possesses numerous year- 



