AND HYBRIDISM IN SALMO FONTINALIS. 1? 



Length of head -Ij, height of body 5^ iu the total length. Eye 

 — diameter 6 in the length of the head, 1 1 diameter from the end 

 of the snont, and 2 diameters apart. Subopercle twice as long- 

 as deep. Teeth normal. Scales — 43 rows between the lateral 

 line and the base of the ventral fin ; 2i rows from the hind edge 

 of the base of the adipose dorsal downwards and forwards to the 

 lateral line. 



Before passing on to the next specimen from Cardiganshire, 1 

 would allude, for comparison, to some examples of brook-trout 

 received from the same locality and from the same donor. 



B. xii. D. 12-15 (^). P. 13-15. Y. 9. A. 10-12 (-^^g), 



128-135 



C. 19. L. 1. TTiTIT^ . 



118-125 



Scales — 13 rows from the posterior edge of the base of the 

 adipose dorsal fin downwards and forwards to the lateral line ; 

 26 rows from the lateral line to the base of the ventral fin. 



(5) Hybrids. — Some excellent anglers have informed me that 

 S'ahno fontinalis has interbred iu the Waudle, and also in Cardi- 

 ganshire waters, with the common brook-trout. I have also been 

 told that the same occurrence has taken place elsewhere. 

 Hunter, we know, was of opinion that hybrids were not produc- 

 tive except in cases where the generative organs were in a state 

 of perfection, a state which might be considered unnatural in 

 hybrids. These views have been considerably modified of late 

 years ; and the opinion of Pallas seems regarded as reasonable, 

 that domestication tends to eliminate hybridism. Be this as it 

 may, we know from the experiments of Easch and others that 

 hybridism between the charr and the trout, and the salmon and 

 the trout, may be brought about, and it has been stated that occa- 

 sionally their offspring are prolific*. 



I have had examples sent to me which certainly appeared (judging 

 solely by external form and colour) that sucli an admixture had 

 resulted. A minute examination, however, failed to confirm first 

 impressions, the small size of the scales of the American trout and 

 its peculiar dentition showing that no reliance could be placed on 



* Mr. Davidson informs me of a hybrid having existed in the East between 

 a Muscovy and a Common Duck. One female laid many eggs of a deep sea- 

 green colour ; but every trial to hatch such proved abortive. Consequently I 

 think it may not be unreasonable to argue that the existence of ova or milt in 

 fish may not be absolute proof of sterility or prolificness. Hei-e the fish-cul- 

 turist's opportunities for observation vfill doubtless prove invaluable. 



LINN. JOTJEK. — ZOOLOaT, TOL. XA'II. 2 



