2 BULL.ETIN 79, UNITED STATES NATIONAX. MUSEUM. 



A dagger indicates that the type is also here. It is to be clearly 

 understood that, especially in unrevised genera, the indication 

 that a given form is in the collection implies nothing more 

 than the presence of a specimen of the animal on which a par- 

 ticular name was based. The sequence of groups is, in its main 

 features, that adopted by Osborn in his "Age of Mammals," 1910, 

 though the arrangement of the famihes and genera has been revised 

 to make it as consistently as possible in harmony with that of 

 the higher groups; that is, to begin with the more generalized 

 forms and end with those showing the highest degree of specializa- 

 tion.^ Under every species and subspecies reference is made to the 

 first publication of the specific or subspecific name. To this, when 

 necessary, is added, (a) reference to first use of current binomial 

 or trinomial, (6) in the case of species described before 1885, but 

 not at that date admitted as valid, reference to establishment as 

 members of the North American fauna, and (c) reference to True's 

 list.^ References to alterations in generic names are also given, 

 but the concordance with the nomenclature of 1885, being sufficiently 

 indicated by the citations under species, is here omitted. The type 

 locality of each form is stated with all possible exactitude; and in 

 revised genera the ranges are given as printed by the author. All 

 questions of nomenclature have been decided in accordance with the 

 International Zoological Code. 



Class MAMMALIA. 



Subclass EUTHERIA. 



Superorder DIDELPHIA. 



Order MARSUPIALIA. 



Suborder PoLYPROTODONTiA. 



Family DIDELPHIID^.^ 



Genus DIDELPHIS Linnaeus.* 



1758. DidelpUs Linn^us, Syst. Nat., ed. 10, vol. 1, p. 54. Type, 

 DidelpMs marsupialis Linn^us. 



1 This portion of the work, together with a review of the status of genera and subgenera, is the result 

 of original investigation; elsewhere the strictly historical method has been adhered to as closely as possi- 

 ble except in cases where it would cause the perpetuation of obvious errors. 



2 No attempt is made with the many species which prove to have been comjwsite as imderstood in 1S85 

 to apportion the name then used to each of the component parts as they now stand. The word "part'! 

 in parenthesis, after the reference, indicates that segregation has taken place. 



3 For discussions of the nomenclature of certain genera of this family see Rehn, Amer. Nat., toI. 24, 

 pp. 576-577, July, 1900; AUen, Bull. Amer. Mus. Nat. Hist., vol. 13, pp. lSS-190, October 12, 1900; 

 Thomas, Amer. Nat., vol. 35, pp. 144-145, February, 1901. 



« Revised by Allen, Bull. Amer. Mus. Nat. Hist., vol. 14, pp. 149-188, June 15, 1901. 



