14 Mindeskrift for J. Steenstrup. XVII. 



grass in the summer (Flower & Lydekker pag. 558). Therefore the crowns of their 

 molars are more flat ; they do not require so much force for crushing and cutting 



2-^-3 



their food ; the molars are reduced, P2— 3 often disappeared, the muzzle often rather 

 long, the muscles not very strong. And consequently the zygomatic arches are not 

 wide, the sagittal crest low, the mandibular articulation not so expanded, processus 

 postglenoideus rather low, the neck-muscles do not cause an antero-posterior com- 

 pression of the hind part of the brain-case, etc. 



Thus we are entitled to say that the resemblances between the skull of Ælu- 

 ropus and Ælurus can all be derived from the convergent development of their teeth 

 which are adapted to crush tough vegetables; but the resemblance between Æluro- 

 pas and Ursus — the form of the bulla, the presence of mg, the construction of p"*, 

 the form of the space between the pterygoids etc. — is due to real generic 

 connection. 



As to the limbs, at the first glance they seem to be more Panda-like than Bear- 

 like; but if the head of Æliiropus is a modified bear-head, the resemblance between 

 the limbs of Æluropus and Ælurus must also be of adaptive nature. But unfortun- 

 ately we are not sufficiently acquainted with its life-habits to give a full explana- 

 tion of the features of the limbs, nor are the muscles known. But as a general 

 rule we may say that the limb-bones of Æluropus differ from those of Ursus and 

 resemble those of Ælurus in being shorter, stouter, more expanded at the ends than 

 in Ursus, and the ridges and other parts of the bones where the muscles are inser- 

 ted, are formed more like those of Ælurus. That seems to me to indicate that the 

 two animals move in the same manner ; no doubt Ælurus climbs trees, the larger 

 Æluropus perhaps climbs on the rocks. 



The presence of an entepicondylar foramen is of no great significance, being 

 generally absent in Ursus, but often present in U. ornatus and according to Gervais 

 (1875, pag. 86) also in Arctotherium bonariense and Hyænarctos. Its appearance in 

 the other carnivorous families is also somewhat irregular like the appearance of the 

 foramen alisphenoideum. According to W. K. Gregory^) its presence may be a pri- 

 mitive feature. — The form and size of the radial sesamoid on the carpus is quite 

 unique among Carnivora, it suggests to us the "os falciforme" of Talpa (though 

 the latter is articulated with the distal end of radius); in Castor we find a se- 

 samoid With the same position and nearly the same size as that of Æluropus^). 

 Also in the foetal carpus of Didelphys (W. K. Gregory 1. c. pag. 440 fig. 9) and in 

 some cHmbing rodents we find a similar bone. Thus its presence may indicate 



') Will. K. Gregory: The orders of Mammals. (Bulletin of the Arner. Mus. of Nat. Hist. vol. 

 XXVII, 1910, pag. 436). 



'■') Flower: Osteology of the Mammalia, London 1885, fig. 96. 



