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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
their food; the molars are reduced, p
2–3
2–3 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
compression of the hind part of the brain-case, etc.
Thus we are entitled to say that the resemblances between the skull of
Æluropus and Ælurus can all be derived from the convergent development of their teeth
which are adapted to crush tough vegetables; but the resemblance between
Æluropas and Ursus — the form of the bulla, the presence of m3, the construction of p4,
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
Bearlike; but if the head of Æluropus is a modified bear-head, the resemblance between
the limbs of Æluropus and Ælurus must also be of adaptive nature. But
unfortunately we are not sufficiently acquainted with its life-habits to give a full
explanation 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
inserted, 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[1] its presence may be a primitive 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
sesamoid with the same position and nearly the same size as that of Æluropus[2].
Also in the foetal carpus of Didelphys (W. K. Gregory l. c. pag. 440 fig. 9) and in
some climbing rodents we find a similar bone. Thus its presence may indicate
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