BLUEBACK TROUT. 
39 
Female . — Similar in form to male but somewhat deeper, with shorter head and head parts, 
excepting larger eye, and smaller fins. Head 4.48 in length without caudal; snout, 3.91; eye, 
5.75; upper jaw, 2.3; lower jaw, 3.48. Depth of body 4.03 in length without caudal; the dorsal 
situated more posteriorly than in male, the distance of its origin from tip of snout about equaling 
distance from origin to upper base of caudal, the distance from posterior end of dorsal base to 
middle base of caudal about equaling distance from front of orbit to origin of dorsal; dorsal 
rays 11, the longest longer than the base of the fin, 1.43 in head; dorsal base 1.28 in longest ray 
and 1.84 in head; distance from posterior end of dorsal base to adipose fin about equaling the 
distance from insertion of adipose to middle base of caudal; about 4.84 in length without 
caudal; distance from tip of snout to base of pectoral about 1.06 in head, and 2.37 in distance 
from tip of snout to origin of dorsal; pectoral equaling ventral in length, 1.19 in head, the dis- 
tance from its base to ventral 3.82 in length without caudal; ventral situated under the origin 
of dorsal nearer tip of snout than middle base of caudal, the distance from its base to origin of 
anal greater than length of head and 4.11 in length without caudal; anal rays 9, the longest 
more than one half distance from ventral to anal, slightly longer than base of anal, and greater 
than distance from anal to caudal, 1.43 in head; distance from posterior end of base of anal to 
lower base of caudal greater than distance from adipose to caudal, containing the least depth of 
caudal peduncle 1.42 times. 
Coloration. — Similar to male but paler; blue of back less decided and with scarcely a trace 
of mottling; median portion of body paler rose; abdomen lemon yellow; body spots much 
smaller and of lighter orange. Dorsal similar to male but with a white dot at base of each ray. 
Pectoral, ventral, and anal fins lighter than in male. 
Specimen 14| inches long. 
Description of Salvelinus oquassa, var., from Rainbow Lake, Maine, from Specimens serving as 
Subjects of the Illustrations in this Paper. 
Male. — Head 4.06 in length without caudal; snout, 3.42; eye, 6; upper jaw, 2.08; lower 
jaw, 1.52. Body symmetrically fusiform, the depth 4.87 in length without caudal; dorsal 
situated midway between tip of snout and middle base of caudal, length of its base about 
equaling length of longest ray, about 1.80 in head, rays 10; distance from posterior end of 
dorsal to adipose about equal to distance from insertion of adipose to middle base of caudal, 
about 4.33 in length of body without caudal; distance from tip of snout to base of pectoral 
equaling distance from dorsal to adipose; length of pectoral equaling length of ventral, 1.5 in 
head, the distance from its base to base of ventral, 3.48 in length of body without caudal; ven- 
tral situated under the anterior third of dorsal nearer tip of snout than middle base of caudal, 
distance from base to beginning of anal 3.9 in length of body without caudal; anal rays 9, its 
