FISHES SALMONIDAE FARIO AURORA 309 



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advance of the dorsal fin, enters four times and a half in the total length. Its profile is 

 fusiform. The head is rather small and conical, forming the. fourth of the entire length, 

 excluding the caudal fin ; the snout is rounded, sub-conical, protruding beyond the lower jaw. 

 It is probable that in larger specimens it protrudes a great deal more, and especially more so in 

 the male than in the female. The mouth is deeply cleft ; the maxillary is rather narrow, and 

 its free extremity extends to a vertical line passing considerably behind the orbit. The teeth are 

 but moderately developed and very acute. An irregular row may be observed upon the shaft of 

 the vomer, and a few smaller ones on the front of the same bone. The lingual series are 

 parallel. The eye is of moderate development, sub-circular in shape ; its horizontal diameter 

 being contained about four times and a half in the length of the side of the head. The opercle 

 is much higher than broad, and narrower above than below ; its situation being very oblique. 

 The sub-opercle is gracefully rounded exteriorly and but moderately developed. The branchi- 

 ostegals are eleven on either side. The anterior margin of the dorsal is equidistant between 

 the snout and the insertion of the caudal fin ; its height is equal to its base, but its posterior 

 margin is not quite the half of the anterior ; it is composed of twelve rays, the anterior two of 

 which being rudimentary. The adipose fin is very slender, and situated opposite the posterior 

 portion of the anal. The latter is deeper than long, but resembles the dorsal in its general 

 outline ; it contains thirfeen rays, the anterior two of which being likewise rudimentary. The 

 posterior margin of the caudal is furcated ; the length of that fin enters about seven times and a 

 half in the entire length of the fish. The origin of the ventrals is situated opposite the fourth 

 developed ray of the dorsal or sixth in the series ; these fins are composed of nine rays, the tips 

 of which do not quite extend as far posteriorly as the tips of the posterior rays of the dorsal. 

 The pectorals are rather small, broad upon their exterior and expanded margin, and composed 

 of fourteen rays. 



Br. 11 : 11 ; D 12 ; ; A 13 ; C 8, 1, 9, 8, 1, 7 ; V 9 ; P 14. 



The rays in all the fins are bifurcated or branched, with the exception of the external caudal 

 rays, and the rudimentary ones, as a matter of course. 



The scales are of but moderate development ; they are sub-elliptically elongated, somewhat 

 irregular in their outline, and imbricated for nearly the half of their longitudinal diameter. 

 Those constituting the lateral line are more elongated than the rest, with the concentric stria 

 obliterated upon their posterior margin (fig. 30.) 



The coloration as observed on specimens preserved in alcohol is very much altered indeed. A 

 uniform greyish tint seem to prevail all over the dorsal region. The sides are silvery, whilst 

 the abdomen appears to have been of a deep orange, which is traceable over the lower fins. 

 The upper surface of the head is uniform greyish black, whilst the cheeks and opercular 

 apparatus are of a pure silver hue. The dorsal fin alone exhibits black spots ; the latter may 

 have existed on the caudal fin. 



Specimens of this species were collected at Astoria, Oregon Territory, by Lieut. W. P. 

 Trowbridge. 



References to the figures. Plate LX.VIII, fig. 1, represents Fario aurora, somewhat reduced 

 in size. 



Fig. 2 is a scale from the dorsal region taken midway between the lateral line and the 

 dorsal fin. 



Fig. 3, a scale of the lateral line. 



