438 Mr. O. Thomas on Tuoo 



gnathion 47 ; diastema 24*5 ; length of upper molar series 

 (crowns only) 12'6; breadth of °^i 4; least height of muzzle 

 on diastema 12. 



Hob. Tehuantepec. Coll. Boucard. 



Type : B. M. 79. 1. 6. 2. 



The type specimen is evidently in summer pelage, as is 

 shown by the extreme sparseness of the fur, the belly being 

 in fact almost naked. 



G. scalops differs from the species to which I doubtfully 

 referred it by its smaller size, rather redder general colour, 

 and, in the skull, by its more flattened forehead, the absence of 

 the supraorbital inflations, less vertical height both in the 

 muzzle and cranial regions, smaller and differently directed 

 paroccipital processes, and smaller teeth. 



Of other species, G. Cherriei, recently described from Costa 

 Eica by Mr. Allen *, is so far smaller as to need no detailed 

 comparison; while 1 owe to the kindness of Dr. Merriam an 

 opportunity of examining a skull of his G. gymnurus^ about 

 which I had previously been rather doubtful, and which I 

 now see has nothing whatever to do either with G. grandis or 

 G. scalops. 



In 1891 the Museum received from Mr. J. H. Hart, of the 

 Trinidad Botanical Gardens, an Opossum which I doubtfully 

 referred to D. philander^ L. This specimen I have hud 

 occasion to re-examine in connexion with a skin sent for 

 comparison by Mr. H. Caracciolo ; and for reasons given 

 below I now think it ought to be specifically separated from 

 the Philander of the mainland. 



In the list of Trinidad mammals the name of D. philander 

 should therefore be altogether struck out and that of the new 

 form substituted. This name I propose should be 



Didelphys {Philander) trinitatis, sp. n. 



Allied to but decidedly smaller than D. philander, L., tlie 

 difference in size being especially marked in the skull and 

 limbs, while the ears and tail are more nearly equal ta, and 

 therefore proportionately longer than, those of that species. 

 Fur close and soft, somewhat straigliter and less woolly than 

 that of the riiilander. Colour much as in the allied species, 

 yellowish rufous above, buff below ; the face greyish white, 

 with a narrow median dark line. Heel without the minute 

 extra external sole-pad generally present in D. philander. 

 Tail very long, furry like the body for about its proximal 



* 15ull. Am. ."\lu>. N. 11. V. p. .'..'.r (,18!).']). 



