Vol. XXVI. pp. 31-34 February 8, 1913 



PROCEEDINGS 



OF TIIF. 



BIOLOGICAL SOCIETY OF WASHINGTON 



FIVE NEW MAMMALS FROM TROPICAL AMERICA. 



BY GERRIT S. MILLER, Jr. 

 [By permission of the Secretary of the Smithsonian Institution.] 



The United Stairs National Museum contains specimens of 

 the following hitherto undescribed mammals from various parts 

 of tropical America. 



Marmosa purui sp. nov. 



Type. — Adult male (in alcohol), No. 105,543, U. S. National Museum. 

 Collected at Hyutanaham, upper Purus River, Brazil, March, L901, by 

 J. B. Steere. 



Diagnosis. — Like Marmosa keaysi (Allen) but smaller: skull with 

 braincase less elevated, interparietal less obtuse anteriorly, and posterior 

 border of nasals not distinctly emarginate; teeth not noticeably different 

 from those of .1/. keaysi, but premolars less compressed, and space 

 between first and second tooth scarcely greater than that between pm 1 and 

 canine; color as in M. keaysi except that the dorsum of manus and pes 

 is concolor with buffy of underparts. 



Measurements. — Type: head and body, 120; tail, 150; hind foot, 19.5; 

 ear from meatus, 19; condylobasal length of skull, 34.6; greatest length, 

 35.0; zygomatic breadth, 17.6 interorbital breadtb, 6.2; breadth of 

 braincase, 11. 8; median depth of braincase, 8.6 ±; nasal, 15.0; mandible, 

 25.0; maxillary tooth row, exclusive of incisors, 13.8; mandibular tooth- 

 row, exclusive of incisors, 14.0. 



Specimens examined. — Two, both from the type locality. 



Remarks. — Dr. J. A. Allen has kindly sent me two skins of the Peru- 

 vian Marmosa. keaysi for comparison with the Purus River animal. 

 Although nearly related, the two forms appear to be readily distinguish- 

 able. The second specimen of Marmosa purui is a breeding female with 

 unworn teeth. It is considerably smaller than the type (in which the 

 teeth are slightly worn): head and body, 110: tail, 125; hind foot, 17; 

 ear from meatus, 18; condylobasal length of skull, 30.6; mandible, 22.2; 

 maxillary toothrow, 12.4. 



8— Pboc. Biol. Soc. Wash.. Vol. XXVI, 1913. (31) 



