100 Merriam JFetc Mammals from Cozumel Island. 



Mr. Nelson tells me that shortly before his visit a pair of yel 

 low Agoutis were introduced from the adjacent mainland of 

 Yucatan. One of these was seen in the woods near San Miguel 

 by Mr. Goldman. 



In 1898 Oldfield Thomas published a list of 5 species of 

 mammals collected on Cozumel by G. F. Gaumer. These are: 

 Nasua narica (-^ nelsoni}, Didelphis marsupialis (-D. cozu- 

 melce), Nyctinomus gracilis, Chilonycteris rubiyinosa, and Arti- 

 beus perspicillatus (Proc. Zool. Soc. London, 1888, p. 129). 

 No bats were obtained bv Nelson and Goldman. 



Nasua nelsoni sp. nov. 



Type from ( 1 ozumel Island, Yucatan, Xo. 108,520, ^ old, V. S. National 

 Museum, Biological Survey Collection. April 8, 1901, E. W. Nelson and 

 E. A. Goldman. Original No. 14,673. 



Characters. &\ZQ small: tail short; color very dark seal brown, griz 

 zled anteriorly. 



Color. Upperparts, belly, legs, and tail uniform very dark seal brown; 

 head and shoulders grizzled with golden fulvous; sides of neck and 

 outer sides of arms grizzled with buffy whitish: throat soiled buffy; 

 ears and stripe on side of neck behind ears whitish; chin and nose all 

 round grayish; gray on upper side of nose forking and sending a gray 

 stripe upward and backward over each eye; lower eyelid and small spot 

 between eye and ear gray; gray of chin separated from color of throat 

 by a broad dusky transverse band. 



Cranial characters. Skull similar in general to that of N. narica from 

 eastern Mexico, but only about two-thirds the size of that species; male 

 with a highly developed, strongly arched sagittal crest; female with 

 smoothly rounded braincase without trace of crest; zygomata and bulla? 

 similar to those of narica but very much smaller; teeth much smaller, 

 particularly the first and last upper and lower molars; first upper molar 

 not only relatively and actually smaller, but differing markedly in 

 shape, the inner side being cut away anteriorly and posteriorly so that 

 the inner cusp stands out by itself much more narrowly and promi 

 nently: first lower molar very small and narrow; last upper molar varia 

 ble but always narrowly subtriangular, the crown much narrower antero- 

 posteriorly than in the mainland species. 



Measurements. Type specimen ($ old): total length 795; tail vertebra? 

 355; hind foot 85. Average of 2 males from type locality: total length 

 780; tail vertebra? 345: hind foot 83. Average of 4 females from type 

 locality: total length 744; tail vertebras 328; hind foot 79. 



Skull. Type specimen (tf): basal length 95; occipitonasal length 95; 

 palatal length 66; greatest zygoma-tic breadth 61; length of molar series 

 on alveoli 16.5. 



