24 ARKIV FÖR ZOOLOGI. BAND 10. N:0 12. 



diurnal in habits, and by that they got the opportunity 

 of enjoying warmth and sunshine during the time when 

 they moved about, and in night time they retired to their 

 holes in the rocks where they were proteoted against the 

 chili of the night. The thick and soft fur of the Dendrohy- 

 rax, so very convenient, not to say necessary, to the noc- 

 turnal forest dweller, was therefore reduced to the compara- 

 tively short and harsh fur of the »Rockrabbit», and so on. 



ProcaYia (Heteroliyrax) sp. n.? 



In the coUection is al so found a skull of a Procavia, 

 collected at Donya Sabuk ^^2 1914, which cannot be referred 

 to P. {H.) hrucei, but unfortunately there is no skin to this 

 skull. It represents stage VI as the tip of m^ is just appear- 

 ing. Theparieto-interparietalsutureisobliterated. Ofthemesial 

 suture between the parietals only the anterior portion can 

 be traced. The orbit is not closed behind, although the 

 postorbital processes both from the frontal and the zygoma- 

 tic arch are rather long. These facts indicate a member of 

 the Heterohyrax-group. The upper incisors are smoothly 

 rounded off on their anterior surface, it is thus a female 

 skull, and at the same time this fact proves that is does 

 not belong to (H.) hrucei in which the upper incisors are 

 angular and ridged in front even in the female. 



From the &r?/cei-skulls from the same locality this skull 

 differs in several other respects. The suture between the 

 supraoccipital and the interparietal is in this specimen 

 strongly and evenly curved, almost forming a complete se- 

 micircle with the concavity in front, while in all the hrucei- 

 specimens the same suture is quite straight and completely 

 transverse, or in the old male even a little convex in front. 



The constriction between the nasal and frontal portions 

 of the skull is quite strong in such a way that the nasals 

 when seen from above appear quite parallel-sided, but in 

 hrucei they are decidedly wider behind. The foremost por- 

 tion of the frontals is on a level with the nasals, but the cen- 

 tral and posterior parts of the same rise considerably above the 

 fronto-nasal plane. In this way the profile contour lias a some- 

 what dog-like appearance with a considerable depression at the 

 anterior portion of the orbits. In this respect the skull in ques- 



