No. 403.] MYRMECOPHAGA AND DIDELPHIS. 577 
The type of the genus Didelphis is, therefore, the last one 
removed — D. opossum} 
The large opossums formerly called Didelphis require a name, 
and the oldest one available is Sarigua Muirhead, with S. vzr- 
giniana as the type. The complete reference is Sarigua Muir- 
. head, Brewster's Amer. Edition Edinburgh Encyclopedia, Vol. 
XII, Part II, p. 505, 1819. The writer wishes to thank Dr. 
T. S. Palmer, of Washington, for calling his attention to this 
name. 
The nomenclature of the opossums is in a very unsatisfactory 
condition, and the group is much in need of a revision, with a 
large amount of material for examination. 
The recognized Linnzan species stand at present as : 
Philander philander (Linnzus). 
Didelphis opossum Linneus. 
Marmosa murina (Linneus). 
The large opossums should stand as : 
Sarigua karkinophaga (Zimmermann). 
Sarigua virginiana (Kerr). 
Sarigua virginiana pigra (Bangs). 
Sarigua virginiana californica ae. 
Sarigua aurita (Wied). 
Sarigua azare (Temminck). 
The species of Didelphis (= Metachirus Burmeister) stand 
as follows : 
Didelphis opossum Linnaeus. 
Didelphis nudicaudata E. Geoffroy. 
Didelphis crassicaudata Desmarest. 
ACAD. NAT. SCIENCES, PHILADELPHIA, 
March 24, 1900. 
1 Some hold that the opossum is not determinable, but the plates in Seba's work, 
referred to by Linnzus, though poor, are recognizable. 
