KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 58. N:0 2. 79 



In the adult »Aulacodus calamophagus », according to Pousargues, 1 the length of 

 head and body is 60 cm., while the tail measures 21 cm., and in a young animal of the 

 same kind the corresponding dimensions are 47 cm. and 18,5 cm. 



In the type specimen of Thryonomys sclateri Thomas from the Nyika plateau, the 

 tail unfortunately was mutilated, b ut its remaining length amounted to 110 mm. It is 

 thus already by this distinct enough, but still better by its small skull which only had a 

 basal length of 69 mm. 2 



Concerning Thryonomys gregorianus Thomas it is not with full certainty known 

 how long tail it has, but as from the same »region » in which the skull, on which this spe- 

 cies was based, a short-tailed Thryonomys skin has been obtained, it is probable that 

 this belonged to Th. gregorianus. It should then have a tail »scarcely longer than the 

 hind foot» (Thomas 1. c. 1897). Thryonomys gregorianus has, however, a very much 

 smaller skull with the basal length only amounting to 72,7 mm. It can thus not be ident- 

 ical with the animal from Rutshuru. 



It remains then Thryonomys harrisoni Thomas & Wroughton from the Lado 

 district. This species as well has been based on a skull together with an imperfect skin 

 and nothing has been communicated about the length of its tail. The skull of Th. harri- 

 soni is, however, much narrower than in the form from Rutshuru, the greatest breadth 

 of the skull being in the former only 52 mm., in the latter at least 61,5 mm. In addition 

 to this the postorbital process is »entirely absent» in Th. harrisoni, but pretty well deve- 

 loped in the Rutshuru form so that in the latter a very pronounced notch is produced 

 between this process and the supplementary process on the squamosal. 



Although plainly distinct from the species mentioned, the species from Rutshuru 

 with regard to its upper incisors appears to be more allied to the gregorianus group than 

 to sivinderianus. The part of the incisor outside the outermost groove measures in the 

 Rutshuru form about 2—2,3 mm., the following space to the second groove about 1,3 

 mm., and the third about 0,8 mm.; the fourth, or innermost is very narrow only about 

 0,3 (or 0,4) mm. These dimensions are a little variable, but the part of the tooth outside 

 the outermost groove is plainly less than the remaining portion, although at the same 

 time much broader than the next section. 



The dimensions of the two skulls are recorded in the following tables. The larger 

 which is known to have belonged to a complete male specimen is to be regarded as the 

 type of the species. 



The stiff and bristly hairs are as usual flattened and grooved on the upper surface. 

 Their concealed parts are grey, the outer parts clarken from brown to black towards the 

 tips. The majority of the hairs are provided with buff subtcrminal rings. On the head 

 and anterior part of the back these rings are less broad, and less numerous, their colour 

 being »yellowish buff» (Dauthénay, 310, 2). On the posterior back they are broader 

 and more dominating, and the colour richer, almost inclining to »oclire» (Dauthénay, 

 313). On the flanks they are much paler, yellowish white. Belly and throat »maize 

 yellow» (Dauthénay, 36, 2 or 3). Lips and chin white, surrounded by maize yellow. In- 



1 Bull. Mus. cTIiist. Nat. Paris, 1897, p. 160. 



2 Proc. Zool. Soc. 1897, p. 433. 



