MACKINAW TROUT. 893 
Habitat, North Atlantic, ascending all suitable rivers in Northern Europe, and the 
region north of Cape Cod; sometimes permanently land-locked in lakes, where its 
habits and coloration (but no tangible specific characters) change somewhat (in Amer- 
ica) var. sebago. 
Diagnosis.—F rom our Lake Trout and Brook Trout the Salmon may read- 
ily be distinguished by the much larger scales and the presence of round, 
black spots on the body and fins. Krom the Quinnat Salmon, the At- 
lantic Salmon may be known by the short anal fin, which has but nine 
or ten perfect rays. 
Habits —The habits of the Common Salmon are too well known to need 
discussion here. It inhabits the Northern Atlantic on both sides, and 
in the spring ascends all suitable streams to spawn, being especially 
abundant in the Canadian rivers. The land-locked Salmon (Salmo salar, 
var. sebago) of the lakes of Maine differs in no structural respect, but 
has different habits resulting from its restriction. This form has been 
especially recommended for introduction into the lakes of the Western 
States. 
GENUS 592. CRISTIVOMER. Gill and Jordan. 
- Cristivomer, GILL and JoRDAN, Man. Vert. 2d Ed., 1878, 356. 
Type, Salmo namaycush, Walbaum. 
Etymology, Latin, crista, crest; vomer, vomer. 
Body elongate, moderately compressed; head long; mouth very wide, the strong 
maxillary reaching beyond the eye; teeth on the jaws and tongue as in the other genera, 
but stronger; a band of strong recurved teeth on the hyoid bone; vomer boat-shaped, 
the shaft much depressed, provided with a raised crest, which is posteriorly free, and 
which is provided with a persistent series of strong teeth; scales small, 175-220 in the 
‘lateral line ; fins moderate; anal fin short; last rays of dorsal and anal not prolonged ; 
caudal fin forked; sexual peculiarities not strongly marked ; species of large size, gray- 
spotted, inhabiting ihe lakes of the northern parts of America. 
This genus should probably be regarded as a section or sub-genus under Salvelinus. 
There is probably but one.species, the Siscowet of Lake Superior (Salmo siscowet, Agas- 
siz), being apparently a local variety of Cristovomer namaycush, distinguished chiefly by 
its extreme fatness. At least, we have failed to find any structural difference of any 
sort, by which the two species may be distinguished. 
101. CrisTIVOMER NAMAYcUSH (Walbaum) Gill and Jordan. 
Mackinaw Trout; Great Lake Trout; Large Togue. 
Saimo namaycush, WALBAUM, dAriedi piscium, 1792.—GUNTHER, Cat. Fish. Brit. Mus., vi, 
123, and of most authors. 
Salmo amethystinus, MITCHILL, Journ. Acad. Nat. Sci. Phila., 1818, 410 (Great Lakes). 
Salmo hoodi, RICHARD3ON, Fauna Bor.-Amer, iii, 1836, 83.—GUNTHER, Cat. Fish. Brit, 
Mus. vi, 151 (Arctic America). 
