APPENDIX. 299 
FAMILY DIDELPHYIDZ (sap7a, Pp. 198). 
GENUS DIDELPHYS (szgra, p. 196). 
By Mr. Thomas (Ann. Mag. Nat. Hist., ser. 2, vol. xiv., 
p. 184, 1894) the sub-genera Metachirus, Philander, Micoureus, 
and Peramys, mentioned in the text, are admitted to generic 
rank. In a later memoir (0. c#¢., vol. xvili., p. 31°, 1896) he 
adopts the name Murmosa in place of AZicoureus, on account 
of priority. 
I@. KOSERITZ’S OPOSSUM. DIDELPHYS KOSERITZI. 
Didelphus koseritzi, Thering, Os Mammiferos do Rio Grande 
dy sul;-p. 6 (1893). 
Characters.—Allied to D. marsupialts, var. aurita and var. 
azare, which Ihering regards as probably entitled to rank as 
distinct species. Differs from the former by the uniformly 
blackish-brown head, which has a sub-circular ochrey spot 
behind the eye. Possibly identical with D. marsupialis, var. 
azare, which Ihering likewise thinks may form a distinc 
species. 
Habitat.—Rio Grande do Sul. 
V@, TRINIDAD OPOSSUM. DIDELPHYS TRINITATIS, 
Didelphys (Philander) trinitatis, Thomas, Ann. Mag. Nat. 
Hist., ser. 6, vol. xiii., p. 433 (1894). 
Characters.—The island form of D. philander, from which it 
differs by its inferior size, relatively smaller skull and limbs, 
but proportionately larger ears and tail. Fur close, soft, and 
somewhat straighter and less woolly than in the mainland form. 
Colour very similar to that of the latter, yellowish-rufous above 
and buff beneath ; the face greyish-white, with a narrow median 
dark line. Heel lacks the minute additional outer sole-pad 
generally found in D. philander. ‘Tail very long, furred like 
