52 REPORT ON A COLLECTION FROM 



MAMMALIA. 

 By W. E. DE WiNTON, E.Z.S. 



Order RODE NT I A. 



Ehipidomys Macconnelli, sp. n. 



The general colour of the entire upper surface rich golden brown ; the fur is very soft, 

 from 11 to 12 millimetres in length, dull black for the greater part of its length with 

 bright red golden tips ; the slightly longer straight hairs have black tips ; the lower 

 surface is dirty white or drab, the fur being dull black with whitish tips, with no line of 

 demarcation between the colours of the upper and lower surfaces. The ears are large, 

 round, and naked, almost black in colour. The hands and feet dirty white, rather darker 

 on the upper surfaces, almost naked. Whiskers long, reaching beyond the shoulders. 

 The tail is brown, only very slightly paler beneath, practically naked, the very minute 

 hairs in no way hiding the scales ; at the extreme tip there is a long pencil of hairs about 

 10 millimetres long, but no l)ushy hairs on the sides. 



Upper incisors dull orange, rather darker than those of the lower jaw. 



Measurements taken from the specimen in alcohol: — Head and body 95 millim., tail 1J.7, 

 hind foot 2i<5, ear 17. 



Skull — greatest length 26'5 ; greatest breadth ll-'S, across brain-case 12-7 ; narrowest 

 interorbital constriction 16 ; length of nasals 9"1 ; basal length 22'6 ; back of incisors to 

 ])ack of palate 11"5 ; incisive foramina 5"9x2'5 ; diastema 7; length of molar series 5; 

 width outside first molar 5-5, outside last molar 59; mandible, tip of incisors to 

 coronoid process 12, to condylar process 17'8, to angle 173. 



The type and only specimen was found on the summit of Rorairaa, Demerara, and has 

 been presented to the Museum by Messrs. McConnell and Quelch. 



The skull is fragile and transparent, with large, smooth brain-case ; the zygomata are 

 very thin and weak, expanding very little beyond the sides of the head in the squamosal 

 region only. The molars are set in almost parallel rows ; the auditory bullae are very 

 small ; the foramen magnum is very large, the surrounding Ijones very thin, especially the 

 basioccipital condyles. 



This new JR,kipiclomy.s is of much the same size as li. vdci'otis, Thos., from Colombia, 

 but the colour is distinct, being much darker above, while the underparts are greyish 

 with dark bases to all the fur instead of being pure white ; then the ears of the new 

 species are large, while those of the Colombian species are very small. Tlie tip of the 

 tail may or may not be distinct, for the end of the tail of the type of 11. microtis 

 appears to me to be wanting. 



The broken state of the skull of R. microtis exckides the possil)ility of a fair com- 

 parison being made, but in the dentition the two species seem very similar. 



