184 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
LUTRA, Linn. 
Lutra, Linn. “ Syst. Nat. I, 1735.” 
Gen. Ch. —Body elongated, feet short, palmated; digits distinct, the central longer than the exterior ones ; tail moderate, 
depressed, rounded at the sides. 
The skull of the otters, in general, resembles that of the Martinae , hut is more depressed, and 
more contracted behind the orbital processes. The top of the skull is nearly straight, and 
almost parallel with the margin of the lower jaw. 
The dental formula is: incisors, ; canines, ^ ; premolars, ^ ; molars, Ld — 1? = 36 . 
The genus is very widely distributed, being found in all quarters of the globe. The species 
resemble each other, and are separated with great difficulty, owing to their plain colors ; they 
differ in the extent and character of the naked muffle, the palmation and hairiness of the feet, 
details of the skull, &c. America has one strongly marked species, with several varieties, 
according to authors; whether the Lutra californica, of Gray, from the Pacific slope, be really 
distinct from that of the Atlantic, is yet to be finally ascertained by the examination of more 
specimens than are now accessible to the student. 
LUTRA CANADENSIS, Sab. 
American Otter. 
Lutra canadensis, Jos. Sabine, Zool. App. Frankl. Jour., 1823, 653. 
F. Cuv. Diet, des Sc. Nat. XXVII, 1823, 242. 
Griffiths’ Cuv. V, 1827, 130. 
Rich. F. B. Am. 1, 1829, 57. 
Fischer, Syn. 1829, 225. 
Pr. Maxim. Reise in das innere Nord Am. 1,1839, 211. 
Dekay, N. Y. Zool. I, 1842, 39 ; pi. iii, f. 1; pi. xxxiii, f. 1, 2, 3. (Skull.) 
Aud. & Bach. N. A. Quad. II, 1851, 2 ; pi. li. 
Giebel, Saugt. 1855, 789. 
Lutra lataxina, F. Cuv. Diet, des Sc. Nat. XXVII, 1823, 242.— Ib. Suppl. Buff. I, Mammif. 1831, 203. 
Fischer, Synopsis, 1829. 
Lutra brasiliensis, Harlan, F. Am. 1825, 72. 
Godman, Am. N. H. I, 1831, 222. 
Lutra hudsonica, F. Cuv. Suppl. Buffon, I, Mammifl 1831, 194. 
Lutra vulgaris, var. canadensis, Wagner, Suppl. Schreb. II, 1841, 256. 
“ Lataxina mollis, Gray”.' 
Lutra canadensis, var. Lataxina mollis, Gray, Aud. & Bach. N. A. Quad. Ill, 1853, 97 ; pi. exxii. 
Sp. Ch. —Length about 4| feet. Muzzle longer than wide, sending down a naked point along the median line of the upper 
lip anteriorly. Under surfaces of the feet so covered with hair towards the circumference as completely to isolate the naked 
pads of the tips. A hairy strip extending forward from beneath the carpus on the palm. Color above, liver brown, barely 
lighter beneath; inferior surface and sides of head and neck dirty whitish. 
General form musteline. Head broad and blunt, neck long. Body depressed, low ; legs 
short. Tail long, tapering, much depressed, about three-fifths as long as the head and body. 
The naked muzzle is quite large, its posterior outline running up into the forehead, so as to 
be as long, or rather longer than broad; this outline is decidedly A -shaped, the acute angle 
behind; the lines are not quite straight, but slightly sigmoid. The anterior outline of the 
1 I have not been able to find this quotation. 
