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ON SOME MAMMALS FEOM COIBA ISLAND, OFF THE 

 WEST COAST OF PANAMA. 

 By OLDFIBLD THOMAS, F.R.S. 



T) Y the kindness of Mr. Rothschild, I have had the opportunity of worlving out 

 -•— -' a small collection of mammals obtained on the Island of Coiba by Mr. J. H. 

 Batty in May and Jnue of last year. The collection is quite a small one, and only 

 consists of comparatively large species ; so that I am unable to institute any 

 comparison between the fauna of Coiba and that of San Miguel as worked out by 

 Mr. Outram Bangs on a collection made by Mr. A. E. Brown.* 



Mr. Rothschild has generously presented to the National Museum most of the 

 e.xamples of all the species contained in the collection. 



Specimens. 



Alouatta pall/ata coihensis subsp. uov. . . . .6 



Cebus kypoleucus Humb. 



Dasyprocta coibae sp. nov. 



Damn rotkschildi sp. nov. 



Didelphis marsupialis buttiji subsp. nov. . 



1- Alouatta palliata coibensis subsp. nov. 



A small insular race of tlie continental ^1. palliata Gray. 



Fur and colour precisely as in the continental form. But there is among the 

 series a good deal of variation in the demarcation or intergradation between the 

 dark colour of the fore-back and the paler loins, and also ia the colour of the mantle, 

 which in some specimens is dull yellowish and in others more reddish. 



Skull like that of the type, but decidedly smaller in all dimensions, except 

 zygomatic breadth, the zygomata being pro|)ortionally more expanded in the smaller 

 form. Nasals narrowed mesially, expanded in front and behind. 



Dimensions of the type, an old male, measured in skin : Head and body, 5(iU ; 

 tail, 580 ; hindfoot (s.u.), 130 ; skull, greatest length, 104-5; basal length, 86-5 ; 

 zygomatic breadth, 79'.5 ; nasals, length in middle line, 15'3 ; breadth anteriorly, 

 13-5; least breadlh, 7-5; interorbital breadth, 11 ; palate length, o:? ; combined 

 length of upper premolars and molars, 33 ; lower jaw, condyle to angle, 62 ; 

 antero-posterior diameter of ascending ramus, 30 mm. 



Type: (-)ld male. Original number, 110. Killed 18 May, 1901. Six 

 specimens. 



The Howler Monkey of Coiba a}ipears to have been reduced in size by its 

 insular habitat in a way that the Cebus has not, for the latter is fully as large as 

 its bretliren on the mainland. 



■-!. Cebus hypoleucus Humb. 

 Six specimens. 



I can tind absolutely no difference, either in size or colour, between these and 

 mainland specimens. Considering the small size of the island, there is a noticeable 

 amount of variation within the series, both with regard to the extension of the white 

 on the arms and sluiulders, and, in the skull, in the height of the nasal bones. 

 • Ameritan Xaturalist, XXXV. p. 631, 1901. 



