318 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
Var. si<^co\vot (Agassiz) J. & G. — Siscowet Salmon. 
r>0(ly short and deep, covered with thick skin, tliere being an exces- 
sive tendency to the development of fatty tissue. Head very short and 
deep, its upper surface broad and sliort, covered by a skin so thick as 
to completely hide the bones; no distinct median carina. . Mouth very 
large, its gape narrower than in nomaycusJt. Teeth weaker than in 
*S'. mniiaifcush ; snpi>lemental bone also shorter and broader. Maxil- 
lary a little more than half the length of the head. Caudal fin well 
forked. Scales rather small, about 175 in the lateral line. Coloration 
as in /S', naniaycmh, but usually paler; fin-rays the same. Lake Supe- 
rior; abundant, but not yet found elsewhere. Very close to the i)reced- 
ing, but difieriug iu the shortness and breadth of the bones of the head 
and in the extreme fatness of the flesh. It is probably a local variety 
rather than a distinct species. 
{Salmo siscoicet Agassiz, Lake Superior, 1850, 333.) 
•* Vomer without raised crest, the chevron only being toothed; red-spotted. (Sal- 
rclhiHs. ) 
a Hyoid bone with a narrow median band of teeth (sometimes lost). 
510. S. oqiiassn. (Grd.) Gill & Jor. — Oquassa Trout; Blue-hack Trout. 
Lody elongate, considerably compressed, less elevated than iu the 
other species ol this genus, the dorsal outline regularly but not 
strongly curved. Head quite small, much smaller than iu any other 
of our trout, its upper surface flatfish. Mouth quite small, the maxil- 
lary short and moderately broad, scarcely extending to the posterior 
margin of the eye. Eye large, 3.| iu head. Jaws about equal. Scales 
small, those along the lateral line somewhat enlarged. Pectoral and 
ventral fins not elongate; caudal fin well forked, more so than iu the 
other species. Preopercle as iu S. fontinalis, but the lower limb more 
develoi)ed; opercles without concentric strim. Coloration dark blue, the 
red spots small and round, much smaller than the pupil, ii.snally confined 
to the sides of the body ; sides with traces of dark bars; lower fins varie- 
gated, as iu /S'. /rndbrn/is. Head 5; depth 5. I). 10; A. 0. Lat. 1. 230; 
gill rakers about G-f 11. L. 12 inches. Smallest and handsomest of ofir 
trout, as yet known only from the Eangeley Lakes, in AA^esteru Alaine. 
(Salmo oquassa Girard, Proc. Acad. Nat. Sci. Phila. 1854, 2G2: Sal mo oquassa Giinthcr, 
vi, 154; Jordan, Proc. U. S. Nat. Mus. i, 81.) 
511. S. iiaresi (Gunther) Bean. 
Greenish above, sides silvery or deep red, with very small red spots, 
much smaller than the pupil ; lower fius deep red, with the auterior 
