and allied East- Aft ican Species. 3i3 



Dimensions in millimetres (measured in the flesh) : — 



Average of 



10 adults. Max. Min. 



Head and bod V 145 165 141 



Tail ". Ill 122 108 



Hind foot 27 29 25 



Adult skull : greatest length 35*6 mm. ; basilar length 30; 

 condylo-incisive length 33'9 ; zygomatic breadth 18'5 ; inter- 

 orbital constriction 4 ; squamosal breadth of cranium 14 ; 

 length of nasals 13; palatilar length 16; length of palatal 

 foramina 7*2 ; alveolar length of upper molar series 73. 



Type localify. Sinien and Shoa, Abyssinia. 



Arvicanthi's ahyssinicus appears to occur over the greater 

 part of Southern Abyssinia. In the Museum collection are 

 two co-types of the species, which, though rather faded, agree 

 very closely with the material more recently collected and 

 from which the above description is taken. In addition to 

 the typical specimens the collection contains representatives 

 of true ahyssinicus from the following localities : — Holota, 

 Addis Alem, Addis Ababa, Barka Plains, LakeTsana, Koosa, 

 Sellin, Arrusi Plateau, and Yah-Yah (N.W. Shoa). 



Meriones lacernatus, Riipp.*, described from Abyssinia, 

 appears to represent ahyssinicus in an abnormal condition of 

 pelage, either during a change of fur or else in a state of 

 erythrism. The skin-dimensions (iiead and body 143 mm., 

 tail 97, hind foot 26'5) are quite similar to those of 

 ahyssinicus. 



(7) ArvicantJiis ahyssinicus sa(uratus, subsp. n. 



A very dark-coloured form, allied to A. ahyssinicus, Riipp. 



In size rather less than hi ahyssinicus, but not maikedly so 

 in the general skin-dimensions. Upper surface of body dark 

 blackish, sprinkled with pale greyish buff, the general effect 

 very much blacker than in ahyssinicus or any of the allied 

 forms. Dorsal stripe well marked, rather more so than is 

 usually the case in the typical species. Flanks similar in 

 colour to back, not paling towards the ventral surface. Face 

 much darker and less buff-coloured^ only the ocular rings and. 

 tip of nose tinted with pale buff. Ears clothed with dark 

 hairs speckled with pale buff. Light patches under and 

 behind ears as in ahyssinicus. Backs of hands and feet dark 

 brownish black speckled with buff ; toes blackish brown. 

 Under surface of body blackish brown, washed with pale 



* Mas. Senck. iii. pp. 90, 115, pi. vi. fig. 1 (1842). 



23* 



