142 Mr. O. Thomas on new 



Skull : greatest lengtli 37"5 ; basilar lengtli 30"3 ; zygo- 

 matic breadth 19*0; nasals IG'5 X 6'7; interorbital breadth 4'2; 

 palatilar length 17; palatal foramina 7; length of upper 

 molar series (grinding-surface) 7'3. 



Boh. Iluwenzori East, 12,500' ("seen up to 13,000' '0- 



Type. ^lale. B.M. no. 6. 7. 1. 54. Original number (353. 

 Collected 18th February, 190G, by R. B. Woosnam. 

 Six specimens obtained. 



This animal is related to the corresponding mountain-form 

 of Mt. Elgon, Otomys Jacksoni^ from 13,200', but differs by 

 its larger size, more uniform coloration, and the possession of 

 only six laminaa on the last upper molar. 



I have had great pleasure in naming this distinct species 

 in honour of the Earl of Dartmouth, to whose generosity this 

 splendid exploration of Mount Kuwenzori is primarily due. 



8. Otomys Denti, sp. n. 



Incisive grooves as in 0. irroratus, but m^ with five laminae 

 only. Colour very dark. 



Size rather smaller than in 0. irroratus. Fur long and 

 fine; ordinary hairs of back about 20 mm. in length. General 

 colour dark blackish brown (darker than " bistre ") with a 

 coppery tinge, the rump almost black, the light rings on the 

 hairs dark tawny. Under surface and inner aspect of limbs 

 slaty black, a few only of the belly-hairs tipped with dull 

 buffy. Upper suiface of hands and feet uniformly brownish 

 black. Tail black throughout, above and below. 



Skull smaller than that of 0. irroratus, more flattened 

 above, its profile not so convex above the orbits, tiie height 

 from tooth-row to supraorbital ridges markedly less. 



Incisive grooves as in 0. irroratus. Molar laminae 4_^. 



Dimensions of the type (measured in Hesh) : — 



Head and body 157 mm.; tail 89 ; hind foot 27 ; ear 21. 



Skull: greatest length 36'6; basilar length 30*3; zygo- 

 matic breadth 18*6; nasals 14*7 X ^''!i; interorbital breadth 4*5; 

 lieight from alveolus of in^ to supraorbital ridge 10*8 ; palatilar 

 length J7; palatal foramina 7'2 ; upper molar series (grinding- 

 surface) 7. 



Hah. Kuwenzori East, 6000'. 



Type. Female. B.M. no. 6. 7. 1. 69. Original number 56. 

 Collected 27th January, 1906, by K. E. Dent. Tiuee 

 specimens. 



This striking swamp-rat is readily distinguishable by its 

 dark coppery colour, flat skull, and the presence of only five 

 lamiuie on the last upper molar. 



