salmonoide^e. 143 



the tip of the snout to the centre of the middle caudal rays. The dorsal vertebrae are 58 in 

 number, and the pyloric caeca varied, in ten individuals, from 49 to 53. The young have 

 paler colours, silvery scales, and about seven arterial blood-red spots on the lateral line, with 

 pale areolae. They descend to the sea and return into the rivers to spawn in the winter time. 

 Individuals varying from sixteen to twenty inches in length contained mature roe. This trout, 

 is not very choice in its selection of food, the stomachs of those which I opened containing 

 river shells, larvae of insects, seeds of various vegetables, bits of straw and charcoal, much 

 sand, small pebbles, the common coralline of our sea-shores broken down, and the roe 

 apparently of its own species. The intestines of the young were rilled with minute crustacese, 

 flies, river-shells, and cod-bait, the last appearing to be a favourite food of the young of the 

 salmon tribe. 



Our Nith Trout possesses many of the characters ascribed to the Salmo trutta by continen- 

 tal ichthyologists *, but in the absence of the power of referring to authentic specimens 

 for comparison, I am unable to give it that appellation with confidence, especially as the 

 descriptions and figures of trutta, by many authors, apply nearly as well to our Salmon-trout. 

 The liberality and kindness of Captain Barou have furnished me with a beautiful stuffed 

 specimen of the Salmo Lemanus of Cuvier, which is said by M. Agassiz to be merely a par- 

 ticular state of Salmo trutta. It has at first sight a very different aspect from our Nith trout, 

 owing to its much paler general colour, smaller and more numerous spots, and somewhat 

 larger scales ; but on examining the details of external structure, the relative proportion of 

 parts, and the dentition, they are found to be very similar to those of the Nith trout. The 

 posterior angles of the gill-cover are, however, more rounded, giving a convex curve to its edge 

 approaching to that of the Salmon-trout, and the length of the under jaw rather exceeds that 

 of the top of the head. I have had no opportunity of examining the viscera of the Swiss trout. 



6. Loch Leven Trout. I am indebted to Mr. Arnott for very fine specimens of this 

 celebrated trout, which, in external form, the proportional size of the various parts of the head 

 and gill-cover, the size of the scales, and the dentition, agrees with the Salmo Lemanus ; the 

 only difference that I can perceive, between the specimens that I have compared, being in the 

 almost white hue of the one, and the deep shades of colour in the other. The scales in both 

 dry in the same manner, producing a small ridge in the centre of each, which I do not per- 

 ceive in other trouts. Three individuals of the Loch Leven trout, that were dissected, had 

 each 73 pyloric caeca, and in one of them 59 vertebrae were counted. The largest of the spe- 

 cimens measured twenty inches and a quarter including the caudal fin, and two inches less 

 to the end of the scales. Its colours were as follows. The back liver-brown, nape hair-brown, 

 top of the head wood-brown, sides of the head and body silvery tinged with rose-red, under 

 jaw, throat, and belly whitish, partially glazed, particularly near the ventrals, with Dutch- 

 orange. The top and sides of the head are marked with round blackish-brown spots, which 

 are largest on the gill-covers, where they equal swan-shot in size. The whole side of the fish, 

 from the ridge of the back to half way between the ventrals and lateral line, is ornamented with 



* Nilsson's character of the LaxKnng of the Swedes, which is his Salmo trutta, applies exactly to our Nith Trout. 



