BLUEBACK TROUT. 
37 
The fins have the same relative position as in the brook trout, but are proportionally more 
developed, with the exception of the adipose, which is considerably smaller; their shape is 
alike, except that of the caudal, the crescentic margin of which is undulated instead of being 
rectilinear. The scales are somew'hat larger, although they present the same general appear- 
ance as those of the brook trout. The lateral line is similar in both of these species. A bluish 
tint extends all along the back from the head to the tail, so that when seen from above, the fish 
appears entirely blue ; hence the name of Blue Back, given to it by the settlers of that neighbor- 
hood. ■ The sides and abdomen are silvery white in the female, and of a deep reddish orange 
in the male, spotted in both sexes with orange of the same hue as the abdomen. The dorsal 
and caudal fins are brownish blue, bordered with pale orange in the male, the pectorals, ven- 
trals, and anal of a fiery orange, blackish blue at their base, with their margin of the purest 
white. When just taken out of the water it is impossible to imagine any thing more beautiful 
and more delicate in the way of coloration in fishes of the temperate zone.” 
Mr. Page said of them (1. c.) that they had no bright vermilion spots, the ventral, anal, 
and pectoral fins bright scarlet but without the black and white lines so conspicuous on the 
Brook Trout, and the tail more forked. 
In Forest and Stream of December 10, 1874, p. 277, Mr. C. A. Kingsbury, of Philadelphia, 
stated that he had received some Bluebacks, a careful, critical examination of which led him to 
believe them to be an undescribed species, and at the meeting of the Philadelphia Academy of 
Sciences of the 17th of November, 1874, he had presented the specimens and given a minute 
description of them under the name of Salmo caeruleidorsus. This communication was referred 
to the Standing Committee on Ichthyology and at the suggestion of Dr. Leidy the specimen 
was sent to Professor Baird who advised him that it was the Salmo oquassa of Girard, and in 
the same paper, on the same page, was published a description of the fish by J ames W. Milner, 
under date of November 29, 1874, to whom it appears Mr. Blackford had sent specimens. He 
stated that the form of oquassa was much more slender and with a tendency to prolongation not 
seen in the Brook Trout; thus in the length of body and of head compared with their lengths, 
the pectoral fin prolonged to a slender point, the two lobes of the caudal extended in the same 
way, showing a decided furcation, and the opercular bones prolonged into a more acute angle. 
On the contrary the maxillary bone extends much less far back of the position of the eye, or 
toward the hinder end or hinge of the lower jaw in the Oquossoc trout. The interopercular 
bone, he states, is jnuch larger in S. oquassa and the suboperculum is wider and the tail in 
Salmo fontinalis is more truncated than in any species it is likely to be confounded with. 
The Maine Commissioners’ Report for 1874, pp. 17, 18, says: “This beautiful little fish 
takes its name from a bluish tint on the back, not unlike the bloom of a plum. They are spotted 
like a trout, and to a casual observer the difference in a basket of fishes would not be noted. 
But like the togue they have only the yellow and black spots but not the red. Their tints and 
