1901.] Allen, Opossums of the Genus Didelphis. 173 



gray phase ; Corpus Christi, 4, black phase ; Nueces Bay, 2, black phase 

 Alice, i, black phase ; Sycamore Creek, i, black phase ; Del Rio, 2 I in 

 black phase, i in gray phase ; Eagle Pass, i, black phase ; Fort Clark, 

 Kinney Co., 8 4 black and 4 gray ; Brownsville, 6 3 in black phase and 3 

 in gray phase. Also additional skulls. 



Mexico : Matamoras, i. 



Total, 31, and 7 additional skulls. 



Didelphis marsupialis texensis differs markedly from D. virgin- 

 tana in the color and markings of the head, and in its much 

 longer tail, but presents no notable cranial differences. It differs 

 from D. marsupialis in the form of the nasals, in its somewhat 

 longer tail, and in the great predominance of the black phase, 

 the prevailing phase in D. marsupialis being gray. 



Didelphis marsupialis tabascensis, subsp. nov. 



Type, No. 100512, Biol. Surv. Coll. U. S. Nat. Mus., Teapa, Tabasco, 

 Mexico, April 7, 1900 ; E. W. Nelson and E. A. Goldman. 



A long-tailed form, with very long nasals, terminating posteriorly in a some- 

 what pointed angle. Apparently not very different in coloration from D. mar- 

 supialis (typica ). Based primarily on seven specimens from Teapa and Frontera, 

 Tabasco, to which are typically referable two from Papantla, three from Cate- 

 maco, and five from Mirador, Vera Cruz ; also 25 from various localities in 

 Chiapas and Guatemala, and 5 from Merida, Yucatan. Of these specimens 

 rather more than one half represent the black phase. The February specimens 

 are in fairly good winter pelage ; the others, which were nearly all taken in 

 April, are more or less worn. In many of the specimens the underfur, the sides 

 of the neck, and the cheeks are more or less yellowish, in some of them strongly 

 so, and in the Mirador specimens the buff tinge is especially strong, being deep 

 buff on the head, neck, and front half of the body, and pale buff on the pos- 

 terior half. Apparently, however, this strong buff tint is due to adventitious 

 staining. 



Measurements. Type, total length, 0,02 mm.; head and body, 460; tail, 

 442 ; tarsus, 69 ; tail ratio, 96. Six males range from 850 to 919 in total length, 

 and 415 to 463 in tail length, with a tail ratio of 95 to 107. Four females range 

 in total length from 811 to 886, and from 368 to 431 in tail length, with a tail 

 ratio of 95 to 112. (For further measurements, including measurement of 

 skulls, see Table V, 



Specimens examined : 



Tabasco : Teapa, 5 3 black, 2 gray ; Frontera, 2, black, and i skull. 



Vera Cruz : Mirador (near Vera Cruz), 5 i black, 4 gray, and i skull ; 

 Catemaco, 2 i black, i gray, and i skull ; Papantla, 2, gray. 



Chiapas: Tumbala, 4, gray; San Cristobal, i, gray; Ocozuatlan, i 

 gray; Tajalon, i, gray; Valley of Comitan, i, gray; Ocuilapa, i, gray; 



