22 MR. F. DAY ON RACES AND [Jan. 15, 



No. 2 was more distinctly parr-marked, but otherwise very 

 similar. It had 1 1 rows of scales between the adipose dorsal fin and 

 the lateral line, as seen in the larger specimen. 19 rows of scales 

 between the lateral line and base of ventral fin. The extent of the 

 cleft of its caudal fin was 0*9, and the length of the longest ray 1'6. 



No. 3 was in the parr livery with 10 well-marked finger-spots on 

 either side, 3 binck spots on the opercle. Fins as in the others, 

 anal greyish in the centre. The upper jaw in the specimen a little 

 shortened, due to injury. 11 scales in an oblique row from the soft 

 dorsal fin to the lateral line. The fish was a male full of milt. 



As a rule, the females were silvery, and were found to have ova, 

 but not quite ripe, requiring from 4 to 6 weeks more. The males, 

 on the contrary, on being pressed, gave ripe milt. The Salmonoids 

 in these ponds seem to be more spotted than such as are obtained 

 from rivers, and though perhaps not of large size are well propor- 

 tioned. The largest taken in the net was 13'5 inches in length. 

 As a rule, fish in the parr livery seemed to be males, most of which 

 were ripe, while the silvery smolts were generally females ; the finger- 

 marks in all were perceptible. These fish made it very evident that 

 the relative growth of the fry does not depend on the size of the 

 pond, quantity of food, or amount of water, as all had been treated 

 alike, yet they varied in length from 4 to 13^ inches. 



Various reasons have been adduced in order to explain why a parr 

 on becoming a smolt (normally about to migrate seawards) becomes 

 of a silvery colour. Davy (' Philosophical Researches,' 1843, p. 250) 

 suggested of the Salmon "that the young remain in fresh water till 

 they have acquired not only a certain size and strength, but also 

 additional scales, fitting them in their smolt stage to endure without 

 injury the contact of the saline medium." Whether by acquiring 

 " additional scales " he intended to mean an additional coat of 

 scales, may be open to discussion, but as the body of the parr is fully 

 scaled, such would appear to be the meaning. Couch, in 1806, ob- 

 served that the silvery colour of Smolts is not due to their acquiring 

 additional scales, but owing to a deposit of bright soft matter, which 

 shines through the transparent scales. Giinther (Intr. Study of 

 Fishes, 1881, p. 632), however, remarks, respecting the river-Trout, 

 that they "frequently retain the parr-marks all their lifetime; at 

 certain seasons a new coat of scales overlays the parr-marks, ren- 

 dering them invisible for a time, but they reappear in time, or are 

 distinct as soon as the scales are removed. When the Salmones 

 have passed this Parr-stage," we are distinctly informed that "a 

 new coat of scales overlays the parr-marks ; " but as these fish do 

 not shed their scales, he seems to advance that an additional or 

 extra coat of scales is developed at certain periods, an opinion, as I 

 believe, held by Davy, but denied by Couch \ 



1 I have received the following communication from Dr. G-adow: — "The 

 development of the scales in Teleostean fishes, as in the Salmon, &c, is as 

 follows :— The cutis (together with the superimposed epidermis) at first forms 

 a slight elevation, the upper or top end of which assumes a backward direction, 

 and this growing or young scale soon ossifies, but not so completely as in Sharks 



