XO, I THE WHITE RHINOCEROS — HELLER 19 



Thomas. 1 At all events no obvious close relationship with any foreign 

 fossil genera has been well established yet. Osborn does not regard 

 as improbable the derivation from a recent common ancestor species 

 showing as great structural differences as the two under consideration. 

 To produce such skull and dental differences as these two living 

 African rhinoceroses now exhibit would require a long period of time, 

 however. It is absolutely certain that they have been distinct generic 

 types through a great length of time. Leaving out of consideration 

 the great differences found in the occipital portion of the skulls of 

 these two genera we have in the structure of the cheek teeth really 

 vast differences. The differences between the teeth of Ceratotherium 

 with their cement-filled fossettes of enamel and the open W-shaped 

 cusps of Diceros are greater in degree than those found in the whole 

 range of the ruminants. Such structural differences are comparable 

 to those found between the Equidse and Bovidae. 



CERATOTHERIUM SIMUM COTTONI 



Xile Square Mouthed Rhinoceros 



(Natives names; Aluru, Kenga) 



1900. Diceros si in us, Thomas, Oldfield : The white rhinoceros on the Upper 

 Nile. Nature, Vol. 62, London, 1900, p. 599. (Lado specimen col- 

 lected by Gibbons.) 



iqoi. Rhinoceros siimts, Holland. W. J.: The Carnegie Museum. Pop. Sci. 

 Monthly. Vol. 59, No. I, New York, 1901, p. 14, text figure. 



1903. Rhinoceros simus, Sclater, P. L. : [Exhibited the front horn of a 



rhinoceros lately obtained on the White Nile and made the follow- 

 ing remarks.] Proc. Zool. Soc. London, 1903, Vol. 2, p. 194. (One 

 horn collected by Hawker.) 



1904. Rhinoceros simus, Gibbons, A. H. : Africa from South to North, 



through Marotseland. London, 1904, Vol. 2, p. 221. (Describes 

 shooting specimen in Lado Enclave.) 



1908. Rhinoceros simus cottoni, Lydekker, R. : The white rhinoceros. Field 



Vol. Ill, London, 1908, p. 319; Game Animals of Africa, p. 38. 

 Trouessart, E. L. : Le rhinoceros blanc, retrouve en Soudan est la 

 Licorne des anciens. C. R. Acad. Sci., Vol. 147, Paris, p. 1352. 



1909. Rhinoceros simus cottoni, Trouessart, E. L. : Le rhinoceros blanc du 



Soudan (Rhinoceros simus cottoni). Proc. Zool. Soc. London, 1903, 

 p. 198, fig. 3. 



1910. Diceros simus cottoni, Roosevelt, T. : African Game Trails, New York, 



191 0, 474. 

 1910. Rhinoceros simus cottoni, Berger, A. : Die von mir auf meiner Expedi- 

 tion in den Jahren, 1908/C9 in Englisch Ost-Afrika und der Lado 

 Enclave gesammelten Siiugetiere, Sitz. Gesellsch. Naturf. Freunde, 

 Berlin, 1910, No. 8, pp. 344, 346; In Afrikas W'ildkammern als 

 Forscher und Jager, Berlin, 1910, p. 430. 



1 Proc. Zool. Soc, 1901, p. 157. 



