282 MB. W. E. DE WINTON ON THE [Feb. 16, 



The figures of the skulls (pp. 280, 281) are taken from those of 

 old wild-killed bulls now in the British Museum, the one from 

 Abyssinia and the other from S. i\frica. 



Mr. Selous tells me that he has never seen a bull Giraffe with a 

 third horn in South Africa, and Mr. Neumann says the same. 



Noticing the great difference in the weight of the skulls of the 

 two sexes, I was curious to put them on the scales : taking the 

 dried skulls of two wild-killed Abyssinian animals, I found that 

 of the male weighed 19 lb. 8 oz., while that of the female only- 

 weighed 7 lb. 6 oz. The bones of the skull of the female are very 

 smooth and thin ; the whole of the upperside of the skull of the 

 male is covered with a rough superficial o?seous growth, which has 

 its centre in the three horns, gradually enveloping the whole of the 

 upper parts of the skull, forming lumps on the supraoccipital and 

 supraorbital bones, and covering the face to the end of the nasals 

 and the cheeks, so that all the true bones are completely hidden. 



Mr. Arthur H. Neumann — to whom I am much indebted for 

 loan of specimens and help in working out the distribution, being 

 well acquainted with the two forms, is perhaps the only hunter 

 who has killed the Two-horned Giraffe both in South and East 

 Africa, and also the Three-horned species, having formerly killed 

 Giraffes in South Africa when they were much more plentiful 

 than they now are and extended farther southward — tells me 

 that on a journey from Mombasa as far as TJsoga, on the route 

 to Uganda, none were noticed but the southern or blotched kind, 

 and that no Giraffes were seen west of the Naivasha Valley, the 

 route taken from JNaivasha to Kavirondo being more southerly 

 than that at present followed by caravans. And writing to me 

 on his recent successful hunting expedition to the northern shores 

 of Lake Eudolf, Mr. Neumann says :— " I only observed the 

 southern variety in the neighbourhood of Athi or Sabaki Eiver; I 

 had a good view of one a little south of that river. The northern 

 species I found from the Tana Eiver northward as far as I went, 

 namely, to the north end of Bassu (Lake Eudolf) ; I mean, of 

 course, the kind with the defined polygonal pattern. Whether or 

 not there are any of this kind south of the Tana I do not know ; 

 but I feel sure that in the direction I went it is the only sort to 

 the north of that river. In some parts, particularly about the 

 Guaso Nyiro, it is very plentiful, far more so than I have ever 

 seen the southern type anywhere. From a little north of the 

 Loroghi Mountains, I met with no more Giraffes until near the 

 north end of the lake, where I noticed a few in one locality." 



Now Mr. Neumann has thus proved that the two forms are not 

 separated by any impassable mountain district or any great river, 

 but that they approach one another on ground much less 

 geographically or climatically distinct than parts within the ranges 

 of either. This proves that there is no intermediate form, and 

 therefore that to both must be given full specific rank. I must leave 

 it to geologists to give a reason for this abrupt breaking off of the 

 species ; it is the more interesting as it marks the southern limit to 

 the range of Grevy's Zebra {Equusgrevi/i),\v\iih\tdoesnot prevent 



