1. SALMO. 91 



Pectoral as long as the head without snout, reaching to the middle 

 of the distance of its root from that of the ventral. Yentral much 

 shorter, equal to one-half of the distance of its root from the anal ; 

 its outermost ray is vertically opposite the ninth of the dorsal. 

 Posterior margin of the caudal fin truncate. 



There are 125 transverse series of scales, counted immediately ahove 

 the lateral line ; the series descending obliquely backwards from the 

 origin of the dorsal fin to that line has twenty-five scales ; that for- 

 wards from the hinder end of the adipose has fourteen scales. There 

 are twenty-two longitudinal series between the lateral Hue and the 

 root of the ventral. The scales are 'very thin, with the hinder margin 

 irregularly roimded. 



Blackish above and on the sides, each scale with a silvery lustre 

 on its hind margin. Lower parts silvery. Sides with numerous 

 black X-shaped spots; opercles with round black spots. Fins as 

 described above. 



19. Salmo orcadensis. 



D. 13. A. 11, P. 14. V. 9. L. lat. 115. L. transv. 25/30. 

 C»c. pyl. 50. Vert. 56-57. 



This species is very similar to S. nigripinnis, but distinguished 

 from it by a broader and stronger maxillary, larger scales on the 

 tail, and a greater number of pyloric appendages. 



Head well proportioned in its shape, and rather short when com- 

 pared with the body ; body rather slender. The posterior point of 

 junction of operculum and suboperculum is nearer to the lower ante^- 

 rior angle of the suboperculum than to the upper end of the gill- 

 opening. Praeoperculum mth the lower limb very indistinct. Snout 

 short, conical. Maxillary as broad and strong as in S. fario ; in 

 specimens 9 inches long it does not extend to below the posterior 

 margin of the orbit. Teeth moderately strong; those of the vomer 

 form a single series, and are persistent. Fins weU developed ; pec- 

 toral somewhat rounded, its length being more than one-half of its 

 distance from the ventral. The caudal fin is distinctly emarginate 

 in specimens 9 inches long, but nearly perfectly truncate in speci- 

 mens 12 inches in length ; it has the lobes pointed. Scales on the 

 hinder half of the tail considerably larger than on the sides of the 

 trunk ; there are about thirteen in a transverse series descending 

 from behind the adipose fin obliquely forwards to the lateral line. 



Sides with more or less numerous black reticulated spots, between 

 which a few red ones are interspersed. Dorsal with black spots. 



Probably a non-migratory species from Loch Stennis, in the 

 Orkney Islands. 



a-h. Twelve and nine inches long, males. Loch Stennis. From the 

 Haslar Collection. 



Sir J. Richardson mentions this trout in the Faun. Bor.-Amer. 

 Fish. p. 142, referring it to the " Frith-Trout " ; but this appears 

 to have the maxillaries feebler, and the scales smaller. 



