320 SIR RAY LANKESTER ON THE [^W- ^5 



2. On certain Points in the Structure of the Cervical 

 Vertebrse o£ the Okapi and the Giraffe. By Sir Ray 

 Lankester, K.C.B., F.E.S., F.Z.S. 



r Received Marcli U, 1908.] 



(Text-figures 60-71.) 



Among the material relating to the Okapi which has been 

 acquired by the British Museum (Natural History), is a fine 

 skeleton of a nearly but not quite adult male, obtained from 

 Major Powell Cotton. It is the skeleton of the individual the 

 skin of which was presented by that gentleman and is exhibited 

 in the public gallery. 



I have made some study of this skeleton, comparing the bones 

 with those of the Giraffe. Since I commenced this study, 

 Professor Fraipont of Liege has published his finely illustrated 

 account of the specimens of Okapi preserved in the Museum of 

 the Congo State at Tervueren near Brussels. 



The most important difference between the general bony 

 skeleton of Okapi and that of Giraffe — as distinct from the 

 cranivim — is one which is pi-esented by the last three cervical and 

 first dorsal vertebrae of the two animals. A certain difference in 

 the form and proportions of the cervical vertebrae — as between 

 Okapi and Giraffe — is what one expects as the necessary 

 correlative of the much greater length of the neck in Giraffe. 

 But the difference goes a good deal beyond this — as a glance at 

 the drawings given in text-figs. 60 and 61, of the vertebrae, 

 cervical 5, 6, 7, and dorsal 1, at once shows. 



The neural spines {neur. in the figures) of the cervical vertebrae 

 of the Giraffe are much shorter proportionately than are those of 

 the Okapi — and this is especially the case in cervical 7. Further, 

 the inferioi- transverse processes (ti. in the figures) — lateral out- 

 growths which in the mammalian vertebral series are peculiar to 

 the cervical region — are very different in the Giraffe from those 

 of the Okapi. In the Giraffe they are of small proportional size, 

 entirely anterior in position on each vertebra (see text-fig. 60). 

 In the Giraffe a right and a left inferior transverse process exist 

 on the seventh cervical vertebra — as well as on the vertebrse in 

 front of it. 



Not so in the Okapi (see text-fig. 61). Whilst cervical 5 (as well 

 as 4 and 3) has a large inferior transverse process (I speak of the side 

 view as given in the drawing and therefore of one only of the pair 

 of lateral processes) which grows downwards (abaxially) from the 

 anterior part of the vertebra — and is larger than the correspond- 

 ing process in Giraffe — cervical 6 has its inferioi- transverse 

 process in the form of an enormous flange or plate extending the 

 whole length of the vertebra. This does not exist in Giraffe : 

 in that animal the inferior transverse process {ti. text-fig. 60) of 



