232 U. SP. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
DIDELP EY S,. linn, 
Didelphys, Linn. Syst. Naturae, I, 1735. 
While the genus Didelphys, in its widest sense, may be considered as possessing all the char- 
acters given under the family head, it is by some restricted to the species with the toes free, 
and the fur of the back thickly interspersed with long coarser hairs. Of quite a number of this 
particular group, but two belong to the United States north of Mexico—these, at the same time, 
being the sole North American representatives of the family. 
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‘ DIDELPHYS VIRGINIANA. 
Opossum. 
Didelphys virginiana, SHaw, Gen. Zool. I, 1800, 473; pl. evii. 
Desm. Mamm. I, 1820, 255. 
Harzay, F. A. 1825, 119. 
Grirr. Cuv. III, 1827, 24, pl._—tIs. V, 1827, 186. 
Temm. Mon. Mamm. I, 1828, 27. 
FiscHer, Syn. 1829, 263. 
Waener, Suppl. Schreb. II, 1841, 37.—Is. V, 1855, 219. 
Dexay, N. Y. Zool. I, 1842, 3; pl. xv, f. 2. 
Warernovuse, N. H. Mamm. I, 1846, 165. 
Bacuman, Pr. A. N.S. 1848, 40. (Development.) 
Micuet, Ib. 46. 
Aun. & Bacu, N. A. Quad. II, 1851, 107; pl. Ixvi. 
Giesex, Siugt. 1855, 708. , 
Burmester, Erlaut. Fauna Braziliens, 1856, 60; tab. v, vi, f. land 3. (Skull.) 
Didelphys marsupialis, Scures. Saiug. III, 1778; pl.cxlv.* (The description and plate exlv, do not refer to the species.) 
Virginian opossum, PENN. Quad. II, 1781, 301; pl. xxxiv.—Is. Arctic Zool. I, 1784, 73. (Leverian Museum.) 
Opossum, St. Hitarre & Cuy. Hist. Mamm. III, 1819; two plates. 
Spr. Cx.—Hairs whitish, with brown tips, imparting a dusky shade. Legs and feet uniform dark brown or black; the fingers 
and toes white. Head throughout yellowish white, chin and top of head scarcely darker. A dusky suffusion around the eye. 
Tail shorter than the head and trunk. Body with long white hairs interspersed. 
Length to occiput, 5 inches; to root of tail, 203; of tail, 143. 
In the above diagnosis I have presented the characters of this species sufficiently well for 
comparison with the D. californica, which it so greatly resembles. According to Audubon and 
Bachman, the Hudson river is its eastern limit; its western and southern are not defined. I 
have not known with certainty of its existence far west of the Missouri, nor in Texas. 
