214 DR. H, GADOW ON THE EVOLUTION [Mar. 18, 



on the bone-core. Forbes remarked that in his specimen " the 

 prong is not yet visible, but may be felt at the base of the pedicel, 

 close to the skull, on the anterior margin of the horn." {Cf. text- 

 fig. 25, III^.) In well-macerated specimens in the Cambridge 

 Museum, the difierence between the rather long pedicle and the 

 decidedly short os cornu proper is well marked. Owing to the 

 continued and active growth of the shoe from the base, the axial 

 point and the prong are gradually pushed upwards, so that the 

 prong comes to lie far above the skull in a level even above the 

 base of the os cornu, which in the adult is thinned out into a 

 non-osseous, tapering, string-like cone of soft connective-tissue 

 and periost. The shoe continues to grow basally, and ultimately 

 engulfs not only the os cornu but also nearly the whole pedicle. 



lY. The Giraffe aind the Okapi. 



It is of no importance to the present investigation whether the 

 few hitherto known skulls of the Okapi are those of young or 

 adult males or females. The skulls exhibit the same tendency 

 towards broad-based swellings on the fronto- parietal and facial 

 regions as in the Giraffe. Even in the latter genus these parts, 

 although slight and bulging, owing to the pneumatic condition of 

 the bones of such a weakly constructed skull, can ill be reconciled 

 with the only reasonable explanation of the genesis of horns and 

 antlers, "We have to assume that the ancestors of the Girafie had 

 stronger skulls, with serviceable antlers, and that these armaments 

 have caused the bosses of the supporting bones, and that in the 

 Giraffe these very armaments have degenerated into now merely 

 ornamental remnants, vanished in the Okapi. It is possible, as 

 Mr Thomas has sagaciously suggested, that the degeneration of 

 these armaments is correlated with the lengthening of the fore- 

 limbs and neck, the animals ceasing to fight with their heads and 

 using the powerfvil fore-limbs instead. This applies obviously to 

 the Giraffe, but not so easily to the Okapi, unless we look upon 

 the latter as the most degraded descendant of the whole group, 

 which, although perhaps never numerous, was certainly more 

 widely distributed in the shape of several genera and species. 

 At any rate, the Okapi represents not the beginning, but the most 

 modern and most modest member of a tribe which has flourished 

 in bygone times. 



There are other proofs that the Giraffe's armaments represent 

 no primitive condition. The bony growths appear loosely in the 

 skin, a condition which finds a parallel in the cases of separate 

 ossification of the os cornu of certain Bovince. Their matrix has 

 become so emancipated from the skull, that they shift their 

 position befoi-e fusing onto the cranium, and their mode of fusion 

 is most peculiar. As Mr. Thomas has expressed it graphically, 

 not only at the base of the growth, but around it, and quite 

 irregularly, there appear little bony nodules, which become 

 amalgamated with the cranium as if wax had been dropped upon 

 it. Such numerous, small and irregularly scattered " osteoderms " 



