1882.] ON HYBRIDS BETWEEN SALMON AND TROUT. 751 



5. On Hybrids between Salmon and Trout. 

 ByP.DAY.F.Z.S. 



[Received December 7, 1882.] 



The hybridism of fishes is a question of very great interest to the 

 zoologist and importance to the piscicalturist, but which, for obvious 

 reasons, is difficult to investigate, it being only those who possess 

 large stock-ponds or peculiarly adapted waters that are able to assist 

 inquirers in this direction or personally aiford the desired infor- 

 mation. 



Among the Salmonidae hybrids have frequently been adverted to 

 as occurring in a state of nature, as well as due to the manipulations 

 of pisciculturists. Fitzinger informs us that Sahno schiffermuelleri 

 must be considered a cross between a Trout and a Charr, and that 

 in the young the reproductive organs merely exist in a rudimentary 

 condition, while they degenerate into adipose tissue in the adult. 



At Sir J. Gibson-Maitland's magnificent piscicultural establish- 

 ment at Howietoun near Stirling some experiments on this subject 

 have been made, at first under the impression that all our freshwater 

 forms of Trout were distinct species ; while others are now in progress, 

 the results of which will be watched with great interest. 



November 25th, 1879, a man arrived at Howietoun with some 

 salmon-milt obtained the previous night ; and this was employed for the 

 purpose of fertilizing some eggs from a four-year-old Lochleven Trout. 

 A few of the progeny were successfully reared ; and one of the last 

 examples was captured in the stock-ponds in my presence, November 

 14th, 1882. It was given me by the owner, and is now on the table. 

 The age of the fish is consequently about 2 years and 9 months, 

 being in fact a grilse in good condition and 1 1 inches in length. 

 B. X. D. 12 (f). P. 12-13. V. 9. A. 11 (|). C. 19. 

 L. 1. 1 18. L. tr. 25/30. Csec. pyl. 62. 



inches. 



Total length of specimen ll'O 



Length of head 2-4 



Length of pectoral fin 1*7 



Distance from snout to base of dorsal fin . . 4'5 



Distance to centre of base of caudal 9*8 



Diameter of eye 0"4 



Distance of eye from end of snout 0*7 



Distance apart 0*8 



Height of body 2-5 



Preopercle forming an almost regular curve, with but very slight 

 appearance of a lower limb. Lower jaw with a slight hook at 

 its extremity. A line taken from the snout to the furthest point 

 of the posterior edge of the opercle passes through the lower 

 third of the eye. Teeth in a double row along the body of the 

 vomer. Scales: 12 rows passing downwards and forwards from the 

 hind edge of the adipose dorsal fin to the lateral line ; 25 rows 



Proc. Zool. Soc— 1882, No. L. 50 



