358 TRICHECHUS. 



87. Trichechus. 



l.lZl. C. 5=i: P. t^\ M. ?=5=l8. 

 — o' I— i' 3—3' 0—0 



Trichechus. Linn., Syst. Nat., 1766, i, p. 49. Type T. rosmarus. 

 Muzzle broad, short, with a group of stiff, bristle-like whiskers 

 on each side; fore feet with five subequal toes each having a flat 

 small nail; hind feet with the fifth toe longest; skin projecting be- 

 yond the nails; small flat nails on first and fifth toes, long, pointed 

 nails on remaining three. Tail rudimentary. 



526. rosmarus. {Trichechus), Linn. Syst. Nat., i, 1766, p. 49. 

 Gcogr. Distr. Coast of Labrador northward into the Arctic 



Ocean, and along the shores of Greenland, boreal islands and polar 

 areas of eastern hemisphere to western Asia. 



Genl. Char. Head small, square, longer than broad; muzzle 

 abruptly truncated; lower jaw pointed; body thick, heavy: tusks long; 

 anterior profile from nasals to point oblique; interorbital constriction 

 moderate; zygoma moderatelj' heavy; inferior border of ramus a 

 gradual nearlj' uniform curve from posterior end of symphysis to end 

 of jaw. 



Color. Yellowish brown; belly and base of flippers reddish 

 brown or chestnut. Bristles yellowish horn color. 



Measurements. Total length, 2450-3650; manus from carpal 

 joint to end of digits, 355-400; pes, from tarsal joint to end of longest 

 digit, 380-450; transverse diameter of tarsus, 178. Length of tusk 

 about 305 outside lips. 



527. obesus. {Trichechus), Illig. Abhandl. d. Berl. Acad. (1804-11), 



1815, pp. 68, 70, 75. 

 rosmarus, Shaw, Gen. Zool., i, 1800, p. 234, fig. 68. (Part.) 

 divcrgens, Illig. Abhandl. d. Berl. Akad. (1804-11), 1815, p. 68. 

 cookii, Fremerj', Bijdrag, tot de naturk. Wetensch., vi., 1831, 



P- 385- 



arcticus. Pall. Zool. Rosso-Asiat., 1831, p. 269, pis. xxviii, xxix. 



Geogr. Distr. Northwest coast of America, in Arctic Sea and 

 Bering Straits, and certain islands in Bering Sea, in Kotzebue and 

 Norton Sounds, and Bristol Bay; also on northeastern coast of 

 Asia. 



Genl. Char. Skull: muzzle narrower than that of T. rosniarus, 

 with the occipital region wider and more massive; tusks longer and 

 thicker, less incurved and more divergent; interorbital constriction 

 very marked; zygoma heavy; interior border of ramus bluntlj' 

 rounded. 



Color. Yellowish brown, dark beneath. There is very little dif- 



