Dr. A. Gunther on the British Charrs. 231 



length of the head ; the length of its base is twice that of its last ray. 

 190 transverse series of scales above the lateral line. Vertebrae 65. 

 Teeth of moderate size. 



This species is not represented by any of the British Charrs that 

 I have examined. The Irish Charrs form quite a distinct group, the 

 characters of which I shall point out hereafter. ^S. Willughbii and 

 S. cambricus have larger scales, much longer pectoral fins, and differ 

 besides in many other points. S. alpinus has the same number of 

 scales ; but in specimens of a corresponding age and size the pectorals 

 are much longer, the maxillary is less developed, &c. The Iceland 

 Charr has the dorsal fin much more elevated. This Swedish S. Sal- 

 velinus may be identical with a part of the specimens comprised by 

 Heckel under the same name. 



b. Sahno alpiyms, L. 



Diagnosis. — Body slightly compressed and elongate, its greatest 

 depth being one-fifth or one-sixth of the total length (to the end of 

 the middle caudal rays). The length of the head equals the height 

 of the body in mature specimens, but is somewhat more in immature ; 

 it is two-ninths or one-fifth of the total ; it is rather less than, or 

 equal to, one-half of the distance between the snout and the vertical 

 from the origin of the dorsal fin. The maxillary extends but little 

 beyond the orbit in the fully adult fish. The eye is one-half, or 

 rather less than one-half, of the width of the interorbital space. 

 The length of the pectoral of the mature fish is more than one-half 

 of the distance of its base from the root of the ventral ; in immature 

 specimens its length is considerably less. Dorsal rays thirteen ; the 

 length of the longest ray is much less than that of the pectoral, and 

 three-fifths or one-half of the length of the head ; the length of its 

 last ray is a little more than one-half or two- thirds of the length of 

 its base. 195-200 transverse series of scales above the lateral line. 

 Vertebrae 62 in the Scandinavian variety, and 59 in the Scottish. 

 Teeth of moderate size. 



At the time when I first compared the Charrs of Windermere and 

 Llanberris* with Linne's and Nilsson's descriptions of Salmo alpinus, 

 I had not had the opportunity of examining specimens from Lapland. 

 Now, having specimens before me which, in all probability, are 

 identical with the species described by Linnaeus and Nilsson, I see 

 that I have misunderstood a part of the description of the former, 

 and that the latter has given his notes from young specimens. When 

 Linnaeus says that the head of his specimen (12 inches long) was 

 \\ inch, he measured only the top of the head from the end of the 

 snout to the ofcciput ; whilst ichthyologists of the present time take 

 the lateral length of the head from the end of the snout to the gill- 

 opening. Nilsson says that S. alpinus has shorter pectoral fins than 

 S. Salveliniis ; this is correct if we examine specimens of the former 

 only 8-10 inches long, but in a mature state S. alpinus has the 

 longer pectorals. Therefore the characters by which I have formerly 

 distinguished the S. alpinus from S, Willughbii and S. cambricus 

 * 'Annals,' Sept. 1862, p. 230. 



