new Afric in Rodents. 



279 



Thanmomys dolichurus (Smut9). 



T. ibeanus, Osgood. 



T. ruddi, Thomas & Wroughton. 



T. cometes, Thomas & Wroughton. 



T. dryas, Thomas. 



T. discolor, Thomas. 



T. surdaster, Thomas & Wrough- 



ton. 

 T. s. polionops, Osgood. 

 T. s. elyonis, Thomas. 

 T. baliolus, Osgood. 

 T. macmitlani, Wroughton. 

 T. m. yazel/cs, Thomas. 



The smaller more typical group of Thamnomi/s, having the 

 postero-internal cusp of m x more highly developed, inclules 

 only T. venustus, Thomas, T. rutilans (Peters), and T. kuru, 

 Thomas & Wroughton. 



Cricetomys gambianus poensis, subsp. n. 



Type from Bubi Town, Bantaberi, Island of Fernando Po, 

 Gulf of Guinea. No. 4. 7. 1. 117, British Museum. Adult 

 male. Collected February 7th, 1904, by E. Seimund. 

 Original No. 83. Presented by the Fernando Po Committee. 



Characters. — Similar to C. gambianus and C. g. dolichops, 

 but with much less white on the tail; skull with a con- 

 spicuous palatal spine, a rather narrow zygomatic plate, and 

 very small audital bullae ; otherwise as in G. gamhvinus. 

 Upperparts dark brown, somewhat paler than in dolichops ; 

 sides of face considerably paler than back ; undei parts pure 

 creamy white to the roots of the hairs, sharply contrasted 

 with upperparts ; feet white except a broad brown stripe in 

 the median metatarsal region ; proximal part of tail dark 

 brown, occupying nearly three-fourths of the entire length of 

 the tail ; terminal fourth of tail soiled white. 



Measurements. — Type: total length G90 mm.; head and 

 body 312; tail- vertebrae 378 ; hind foot (s. u.) 65 ; ear 44. 

 Skull of type : greate-t length 74*8 ; basilar length 61*5 ; 

 zygomatic breadth 32'6 ; nasals 30*5; least interorbital 

 breadth 102 ; postpalatal length 23*8; diastema 24 ; palatine 

 slits 7*4 ; maxillary tooth-row 10*6. 



Remarks. — The most distinctive characters of this form are 

 the extent of the dark colour on the tail and the presence of 

 a well-developed spine on the posterior border of the palate. 

 The palatal spine is constant in the nine specimens examined 

 from Fernando Po. It is slightly developed in two skulls 

 from Gold Coast, but others from Gold Coast, Liberia, and 

 Gambia do not possess it nor is it found in any of the large 

 number of specimens examined from Central and East Africa. 

 The type of gambia7ius, which has been on exhibition for 

 many years, is greatly faded and untrustworthy for colour- 

 characters, except as to the proportion of light and dark on 

 the tail. In this respect it differs markedly from poensis, the 



