MACKINAW TROUT. 893 



Habitat, North Atlantic, ascending all snltable rivers in Northern Europe, and the 

 region north of Cape Cod ; sometimes permanently land-locked in lakes, where its 

 habits and coloration (bnt no tangible specific characters) change somewhat (in Amer- 

 ica) var. sehago. 



Diagnosis. — From 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. From 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 52. CKISTIVOMER. Gill and Jordan. 



Cristivomer, Gill and Jordan, Man. Vert. 2d Ed., 1878, 356. 



Type, Salmo namaycuah, Walbaum. 

 Etymology, Latin, crista, crest ; vomer, vomer. 



Body elongate, moderately compressed ; head long ; month very wide, the strong 

 maxillary reaching beyond the eye ; teeth on the jaws and tongue as in the other genera, 

 , bnt 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 ; 

 oandal fin forked ; sexual peculiarities not strongly marked ; species of large size, gray- 

 spotted, inhabiting the lakes of the northern parts of Americk. 



This genus should probably be regarded as a section or sub-genus nnder Salvelinua. 

 There is probably but one Species, the Sisoowet of Lake Superior {Salmo siscoivet, Agas- 

 siz), being apparently a local variety of Cristovomer namaycush, distinguished chiefly by 

 its extreme fatness. At least, we have failed to find any sfcmctural difference of any 

 sort, by which the two species may be distinguished. 



101. Cristivomer namaycush (Walbaum) Gill and Jordan. 

 lTIack.ina\f Trout; Great Liake Trunt; Liar^e Togne. 



Salmo namaycush, Walbavm,- Artedi piseium, 1792. — Gunthbr, Cat. Fish. Brit. Mus., vi, 



123, and of most authors. 

 Salm^ amethystinus, Mitchill, Journ. Acad. Nat. Sci. Phila., 1818, 410 (Great Lakes). 

 Salmo hoodi, Richardson, Fanna Bor.-Amer, iii, 1836, 83.— Gunthbk, Cat. Fish. Brit. 



Mus. vi, 151 (Arctic America). 



