DE. E. EAY LANKESTEE ON OKAPIA. 305 



facts, and to include in the present memoir an outline sketch, prepared under his 

 direction (text- fig. 15, p. 304), of the skull of the adult male. 



The specimens received in Brussels in May 1902 are the skin of an adult female 

 and the skull and most of the bones of an adult male. The male skull bears (as shown 

 in text-fig. 15) bony horn-cores of a conical shape, about three inches in length. 

 They are much deflected so as to point backwards. In the skin of the female 

 (Dr. Forsyth Major states) there are (although the skull is wanting) bony horn-cores 

 of about two and a half inches in length. The dentition of the male skull and of the 

 lower jaw belonging to it are well preserved, and leave no doubt as to the adult 

 character of the specimen. It is remarkable that, whilst differing greatly in age from 

 our larger specimen, and having developed the large and powerful bony ossicusps 

 which are only represented by the frontal tumescences of our skull, yet the new adult 

 male skull is very little larger than our larger specimen. The measurements of the 

 two are as follows : — 



Sir Harry .Johnston's Male adult skull, 

 larger specimen. Brussels. 



From occipital crest to front margin of nasals . . . 375 mm. 377 mm. 



Maximum width (at zygomatic arch) 18.2 mm. 178'5 mm. 



The margin of the orbit is sharper in the Brussels skull than in ours. There is no 

 indication of an " ossicusp " in connection with the swollen base of the nasals. The 

 skull is in very fine and perfect condition, and will aff'ord data for complete comparison 

 of the base of the skull and the adult dentition with that of the Giraife and of 

 Samotherium. The periotic capsule and tympanic bulla are of much larger size 

 relatively than in Giraffa. This agrees with the relatively large size of the external 

 ear or auricle in Okapia. 



The important and striking feature in the Brussels skull is the presence of supra- 

 frontal ossicusps. The doubts expressed in my memoir in the preceding pages are 

 thus resolved. Though I had definitely recognized the possibility of the development 

 of such ossicusps in older specimens than ours, yet it must be admitted that I was 

 inclined rather to favour the supposition that outgrowths of so large and well- 

 developed a character as those which are now shown to exist would not be found in 

 the adult Okapi. Their presence tends to bring Okapia into very close agreement with 

 Samotherium. It is remarkable, in view of what is known as to the development of 

 the ossicusps on the parietals of Giraffa, that Okapia should attain to practically adult 

 size without having its ossicusps more strongly developed than they are in Sir Harry 

 Johnston's larger specimen. I can hardly doubt now that some osteogenetic, if not 

 actually osseous, cone was present between the skin and the supraorbital tumescence 

 of the frontal in that specimen and was lost in cleaning the skin. 



We do not yet know the facts as to the mode of development of the horns of the 



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