568 PROCEEDINGS OF THE NATIONAL MVSEUM. vol.xxiv. 
marine and anadromous, living and growing in the sea. and entering 
fresh waters to spawn. Still others live in running brooks, entering 
lakes or the sea as the occasion serves, but not haliitually doing so. 
Others again are lake fishes, approaching the shore, or entering brooks 
in the spawning season, at other times retiring to waters of consider- 
a1)le depth. Some of them ai-e active, voracious, and gamy, while 
others are comparatively defenseless and will not take the hook. The 
large size of the eggs and their lack of adhesiveness, with the ease by 
which the eggs iw^lj be impregnated, render the Salmon and Trout 
especially adapted for artificial culture. The Salmonidte are of com- 
paratively recent evolution, few of them occurring as fossils, except 
in the most recent deposits. The instabilitv of the specific forms 
and the lack of sharply defined specific characters may be in part 
attributed to their recent origin, as Dr. Giinther has suggested. 
a. Mouth deeply cleft, the long lower jaw articulating with the quadi-ate bone behind 
the eye, the maxillaries rather narrow. 
h. Salmoninse. Dentition strong and complete; conical teeth on jaws, vomer, and 
palatines; tongue with two series of strong teeth (sometimes deciduous in very 
old specimens) ; scales small. 
c. Anal fin elongate, of 14 to 17 developed rays; gill rakers 20 to 40; branchios- 
tegals 12 to 16; vomer narrow, long, flat, with weak teeth; species spotted 
with black, if at all Oncorhynchvs, 1. 
cc. Anal fin shorter, of 9 to 13 developed rays; gill rakers 10 to 15; branchioste- 
galsl0tol4. 
(1. Vomer flat, its toothed surface plane; teeth on the shaft of the vomer in 
alternating rows or in one zigzag row, those on the shaft placed directly 
on the surface of the bone, not on a free crest; posterior vomerine teeth 
sometimes deciduous; species black spotted Salmo, 2. 
dd. Vomer boat-shaped, the shaft strongly depressed, without teeth; hyoid 
bone with very weak teeth or none; species not anadromous. 
e. Scales moderate, silvery; l)ody covered with small, black spots; head 
flattened above, the jaws long Hucho, 3. 
ee. Scales small (about 200); body with round, red, whitish or yellowish 
spots;' head not depressed Salvclinus, 4. 
aa. Plecoglossinfe. Dentition feeble; premaxillaries with a few pointed teeth; teeth 
of maxillaries and of lower jaw broad, truncated, serrate lamell?e, movable, 
each in a fold of skin; inside of mouth behind lower jaw with folds of skin; 
tongue with minute teeth; vomer with few or none; scales very small. 
Pkcoglossus, 5. 
1. ONCORHYNCHUS Suckley. 
QUINNAT SALMON. 
Oncorhynchus SvcKh^Y, Ann. Lye. Nat. Hist. N. Y., 1861,' p. 312 (scouleri). 
II/ps{f(mo Gihh, Proc. Ac. Nat. Sci. Phila., 1862, p. 330 (l-ennerJi/i). 
Body elongate, subf usiform, or compressed. Mouth wide, the max- 
illary long, lanceolate, usually extending beyond the eye; jaws with 
moderate teeth, which become in the adult male enorraoush' enlarged 
in front. Vomer long and narrow, Hat, with a series of teeth l)oth on 
the head and the shaft, the latter series comparatively short and weak; 
