i goo.] Allen, New American Marsupials. . 1 95 



Measurements. Total length, 534 mm.; head and body, 251 ; tail, 283 ; hind 

 foot, with claws, 39, without claws, 36. 



Skull, total length, 66 ; basal length, 62 ; length of nasals, 32 ; upper tooth- 

 row from canine to posterior edge of last molar, 25.5 ; palatal length, 38 ; zygo- 

 matic breadth, 32 ; mastoid breadth, 19 ; least interorbital breadth, 8.5. 



This species is nearly related to Metachirus quica (Temminck, 

 ex Natterer, MS.), of which it is the Central American represen- 

 tative. The type locality of M. quica may be considered as the 

 coast region of Brazil just south of Rio de Janeiro, Temminck 

 having apparently described the species from Natterer's speci- 

 mens collected there, he also adopting Natterer's manuscript 

 name. It rather closely agrees with Mr. Thomas's description of 

 Didelphis (Metachirus) opossum (Cat. Marsup. and Monotr. Br. 

 Mus., 1888, p. 329), to which he there refers D. quica, Temminck. 

 Metachirus opossum (Linn.), however, judging from Seba's de- 

 scription, on which Linnaeus's name was exclusively based, was a 

 very different animal, especially as distinguished from D. quica by 

 Temminck in his monograph of this group (Monogr. de Mamm., 

 I, p. 41) ; the upper parts being described by Seba as " chatain 

 obscur " and by Temminck as " roux de rouille ou canelle." In 

 either case the type locality is most probably Surinam ; Tem- 

 minck's specimens were, he states, from Surinam, and Seba's 

 specimens were from either Surinam or eastern Brazil. In pro- 

 viding, for convenience, a patrie for D. opossum, Surinam may be 

 properly taken as its type locality. 



The locality of the type of M. fuscogriseus is unfortunately not 

 definitely known ; the specimen was found in a bunch of ban- 

 anas in unloading a fruit steamer from a Central American port, 

 most likely Colon, after its arrival alive in New York harbor. 

 According to Alston (Biol. Centr. Am. Mam., p. 199) this form 

 of Opossum ranges from southern Mexico to Costa Rica. 



Metachirus tschudii, sp. nov. 



Didelphys myosurus TSCHUDI, Fauna Peruana, I, 1844, 145. Not of 

 Temminck. 



Type, No. \\\\% , ? ad., Guayabamba, Peru, altitude 5500 feet, August 30, 

 1894 ; coll. O. T. Baron. 



Above yellowish gray-brown, darker (distinctly black) along the median line, 

 more grayish over the shoulders, and more yellowish brown on the sides, with 

 a decided rusty tinge on the hinder part of the sides, from the region of the 



