NOTE AS TO THE OCCURRENCE AND THE ABSENCE OF OSSICONES 

 IN SPECIMENS OF OKAPI, AND AS TO BROAD AND NARROW SKULLS. 



The fact that very small, apparently young, " ossicones," destined to develop to full 

 size and to become ankylosed to the skull, have been found in a full-sized specimen of 

 Okapi (Skull C, figured in Plate 4, fig. 1, and Plate 8, fig. 1) makes it uncertain 

 whether the presence of these structures can be rightly regarded as a character of the 

 male, or that their absence is to be held as a character of the female. The large skull C 

 (Rowland Ward's specimen purchased by the British Museum) is not that of an adult, 

 although probably full-grown. In this specimen, .as in Sir Harry Johnston's large 

 specimen (Skull A), and in Mr. Boyd Alexander's (Skull D),the three deciduous molars of 

 the upper jaw are still in use. The three individuals were approximately of the same age 

 and sub-adult. In A there is no roughness (though there is a " vascularized " patch as 

 stated in my original description of it) on the frontal bone corresponding to the attachment 

 of an ossicone, and hence I concluded (when describing it ten years ago), in view of its 

 large size, that this individual was permanently hornless. But it is necessary to mention 

 here that the taxidermist, who mounted the skin belonging to this skull for the British 

 Museum, found a small fibrous body on each side in the integument of the head corre- 

 sponding in position to the ossicones, and I do not doubt (now that the small bony 

 ossicones of Sknll C, found in the same position, have become known to me) that these 

 little lumps in the specimen A were commencing ossicones. Unfortunately they were not 

 preserved. In "Ward's specimen (Skull C) the skull is as free from any rough growth, 

 indicating the attachment of the ossicone on either side, as it is in Sir Harry Johnston's 

 specimen (Skull A). On the other hand, the skull (D) of Mr. Boyd Alexander's specimen 

 has a roughly marked area on each frontal bone and two fairly large but immature 

 ossicones, which, though separate, fit on to the roughened patches. I have had, it 

 therefore appears, no Okapi skull in my hands which was devoid of ossicones or 

 detached commencements of them, and yet was adult or sub-adult. On the other 

 hand,M. Fraipont has recorded at least one such specimen, and this (No. 48t>) was trans- 

 mitted to the Tervueren Museum as that of a female (Plate 1G, fig. K). Though it may 

 very possibly be the case that the adult female Okapi has no ossicones, I think that it 

 must be regarded as still a doubtful question as to whether this is the case. Full-grown 

 skulls without ossicones may develop these structures later. The rare absence of ossicones 

 in a truly adult specimen may be due, not to sex, but to individual variation. In marked 

 contrast to the Okapi, the Giraffe is born with the ossicones in a soft uncalcified condition 



