474 MR. OLDFIELD THOMAS ON THE [Nov. 1 9, 



The author briefly discussed the nature and origin of the bony- 

 growths on the skull of the Giraffes, to which the name " horn " was 

 commonly applied. He was of opinion that they were multiple in 

 origin, comprising occipital, parietal, and orbital pairs, as well as a 

 median series. The Giraffidaj were in this respect, as in some others, 

 more primitive than either the Cervidsa or Bovida?, in which a single 

 pair of these bony growths has become greatly specialized, and 

 either developed as naked antlers, freed from integument (Cervida?), 

 or cased over by a protective corneous product of the epidermis 

 (Bovidse). There was no sufficient reason for regarding the horns 

 of the recent Giraffe as degenerate, or for supposing the Okapi, if 

 hornless, to have descended from horned ancestors. The continuity 

 in one plane of the ba si-cranial and basi-facial axes, instead of the 

 meeting of the planes of these two axes at an angle, was a primitive 

 character presented by the Okapi and in a less degree by the Giraffe. 

 This coincidence of the plane of the base of the skull and of the face 

 was found also in the more primitive Cervidsa (e.g. Alas), but not iu 

 any of the Bovidce, where the angle was very strongly marked. The 

 absence of the canine tooth in the upper jaw of the Okapi and the 

 Giraffe might be adduced as ground for supposing that the horns had 

 been at one time more largely developed than at present, since in 

 those Buminantia which were admittedly in a primitive condition in 

 regard to defect of horns, the upper canine teeth were large and 

 effective weapons (Moschus, Tragulug, Vamelus). It was, however, 

 maintained by the author that it did not appear to be a legitimate 

 inference that the upper canine teeth could only disappear when 

 horns had taken their place as weapons, since there were many 

 instances to the contrary in the mammalian series, and it would 

 hardly be justifiable to suppose that Okapia must have descended 

 from a horned ancestor because the upper canines had disappeared, 

 although due weight should be given to this argument. 



This memoir will be published entire in the Society's ' Trans- 

 actions.' 



The following papers were read : — 



1. On the Five-horned Giraffe obtained by Sir Harry 

 Johnston near Mount Elgon. By Oldfield Thomas, 

 F.R.S., F.Z.S. 



[Keceived November 19, 1901.] 

 (Text-figures 42-48.) 



Shortly after his discovery of the Okapi, Sir Harry Johnston 

 made an exploring trip to the Guas' Ngishu Plateau, just south-east 

 of Mount Elgon, and found it to be extremely rich in large game 

 of all sorts. Among other animals he saw Giraffes of an un- 

 usually large size, and on killing some specimens for the National 



