78 DR. C. I. FORSYTH MAJOR ON THE OKAPI. [June 3, 



The four or five stages in the evohition of the Giraffine skull 

 are therefore, beginning from the most generalized : — 



1 . Hoi'nless — presumably female — Palceotragics (^Samothermm) 

 (text-figs. 8 & 9, p. 74). 



1 a. Horned skulls of Palmotragus (tSamoiherium) (text-figs. 6, 

 p. 73, & 10, p. 75) ; all presumably males. 



2. Okapia (text-fig. 7, p. 73). 



3. Giraffa camelopar dolls ccqiensis (text- fig. 11, p. 76). 



4. Giraffa reticulata (text-fig. 12, p. 76). 



As to the dimensions and proportions of tJie limbs and neck, 

 the skeleton shows, still more conclusively than the skin, that the 

 Okapi scarcely difiered in this respect from the ordinary type of 

 Ruminants. 



In the Giraffe, as is well known, both fore and hind limbs are 

 much elongated, the former longer than the latter. By adding 

 together the longitudinal dimensions of the three principal bones 

 in each of the limbs, viz., humerus, radius, and metacarpal in the 

 anterior, and those of the femur, tibia, and metatarsal in the 

 posterior, we arrive at the following proportions of the two :■ — 



Ant. Post. 



Cape Giraffe (Gaudry) 2010:1835 =1000: 912-9 



Abyssinian Giraffe (Brit. Mus.) . . . 2256 : 2079-5= 1000 : 921-8 



Senegal Giraffe (Gaudry) 1770 : 1690 = 1000 : 954-8 



Okapi .■ 948: 974 =1000:1027 



A species of Palmotragus {Samo- 



therium) 1295:1304 =1000:1007 



In the Antelopes and Ruminants generally the hind limb is 

 almost always longer than the fore limb ; in some Antelopes, 

 however, both have almost equal length, but the radius is always 

 shoi'ter than the tibia {Gaudry). Taking, therefore, the length of 

 the radius as 100, we find the following proportions between the 

 length of the radius and the tibia : — 



R. T. 



Taurotragus oryx 100 : 120 



Hippotragus equinus 100 : 1 18-8 



Bos 100:117 



Oka2na 100: 99-7 



Three species oi Samotherium (Palceotragiis) ... 100 <^ : 97 



[: 95 



Helladotherium duvernoyi from Pikermi 1 00 : 86 



Senegal Giraffe 100: 83 



Abyssinian Giraffe 1 00 : 79 



CapeGiraffe 100: 75 



The fore and hind limbs are therefore of about equal length in 

 the Okapi, and the same may be said of the Samotherium group. 

 In the Giraffe the fore limb is longer, and in Ruminants 

 generally it is shorter., than the hind limb. 



The longitudinal dimensions of the cervical vertebrce show the 



