128 



PROF. E. RAY LANKESTER ON 



[Feb. 5, 



(supposed to be those of males) are longer and narrower than the 

 equally large or larger skulls devoid of any bony cones in connec- 

 tion with the frontals (supposed to be those of females) *. What- 

 ever opinion is held, or whatever decision may be ultimately 

 arrived at in regard to these two types of skull, it is the fact that 

 they are veiy distinct from one another and that all the Okapi skulls 

 which I have examined can be definitely assigned to one or the 



Text-fig. 50. 



Rudimentaiy free ossicone of hemispherical shape from the skin overlying the frontal 

 bossed region of the skull of an Okapi of the broad-skulled tj^pe — sub-adult 

 (deciduous molars very much worn, premolars not yet visible; third lower molar 

 in use on both sides, fifth cusp shows slight wear). 

 a, natural size; h, enlarged. 



Text-fie. 51. 



Section of the ossicusp drawn in text-fig. 50, to show the incomplete ossificati'ion. 



other of these two types. There is no third form known. The 

 two types may perhaps be best distinguished as 0. johnstoni (the 

 name I gave to the broad hornless sub-adult skull accompanying 



* One of these broad-skulled specimens has, however, been found to possess a pair 

 of completely detached bonj^ ossicones of minute size embedded in the integument. 

 The specimen is a little older (as indicated bj^ the dentition) than Sir Harry John- 

 ston's larger individual (that mounted in tbe British Museum), but is not quite 

 adult. It belongs to Messrs. Rowland Ward. I give here figures of the minute 

 ossicone (text-figs. 50 & 51). 



