242 Howell— Three Nt^m Shanks. 



Bemarks. —This species differs strikingly in external characters from 

 Spilogak inierru'pta of the plains, while from leucoparia and gracilu it 

 may be readily distinguished by its skull characters. It is apparently 

 a mountain animal, but is at present known from only two localities — 

 Arkins and Estes Park, Colorado. 



Spilogale angustifrons sp. nov. 



Type from Tlalpam. Valley of Mexico, $ adult. No. 50,82.'), U. S. Nat. 

 Mus., Biological Survey Collection. Collected Dec. 15, 1892, by E. W. 

 Nelson and E. A. Goldman. Original number, 4035. 



Oenerul characters.— 9>\'/,^ svaa\\\ coloration as in *S'. mnhigva, but usu- 

 ally without the white bands on thighs. Skull slender, and without 

 prominent ridges. 



Skull. — Similar to that of ambigua, but smaller and narrower; cranium 

 liighly arched; rostrum narrow; audital bulla? relatively large and high: 

 molars smaller than in ambigua, the carnassial teeth decidedly so. 



Measure7nentn.—Av ev2ige of 3 adult males from type locality: total 

 length, 345; tail vertebra?, 130; hind foot, 40. Skull (of type): basilar 

 length, of Hensel, 43; zygomatic breadth, 31.3; mastoid breadth, 27.5: 

 interorbital breadth. 13. 



Remarks. —This form belongs with the group of narroM-skulled species 

 inhabiting the eastern United States, in which group ambigua also be- 

 longs. Intergradation with the latter species is probable, though no in- 

 termediate specimens have been examined. The present form occupies 

 the southern portion of the Mexican table-land, from Guanajuato to 

 Chiapas. 



Spilogale angustifrons tropicalis subsp. nov. 



Type from San Mateo del Mar. Oaxaca. $ adult. No. 73,523. U. S. Nat. 

 Mus., Biological Survey Collection. Collected May 16. 1895. by E. W. 

 Nelson and E. A. Goldman. Original number, 7958. 



General cliaractern. — Similar to augu.'ififron.s; but larger: skull with 

 smaller teeth and larger mastoid capsules. 



Skull. — Larger and more angular than that of angvHtifrom: mastoid 

 capsules more inflated; audital bulhe flatter: rostrum broader: upper 

 molars and last lower molars relatively smaller. 



Measurements. — Average of 3 adult males from type locality: total 

 length, 378; tail vertebrae, 144; hind foot, 44.7. Skull (of type): basilar 

 length of Hensel, 47; zygomatic breadth, 33: mastoid breadth, 30.5: inter- 

 orbital breadth, 14.5. 



Remarks. — This form occupies the tropical lowlands of Oaxaca, inter- 

 grading apparently with angustifrons in the neighborhood of Tehuan- 

 tepec. Its skull resembles that of ambigua quite closely, but has 

 decidedly smaller teeth and larger mastoid capsules. 



