388 Dli- &• ELLIOT SMITH ON 



to its pallial development, a fact wliicli miglit be explained in. the manner I have 

 attempted to explain the shortcomings of Myrmecophaga when contrasted with the 

 Carnivora. In the subsequent development of the post-Oreodont mammals we find 

 increasing complication and specialization of various anatomical systems, in corre- 

 spondence with the varying conditions of life. This is seen in the jaws and other parts 

 of the skull, in the structure of the limbs, in the modifications of the alimentary tract, 

 but progress is especially noticeable in the brain. In all the existing descendants of the 

 Creodont stock the brain has increased enormously in size, but in some groups to a much 

 greater extent than in others. 



In an interesting memoir, Max Weber has discussed the peculiar contrast between 

 the size of the brain in the Hippopotamus and the Elephant *. In two animals of 

 approximately the same weight, one (the Hippopotamus) has a brain of 582 gr., while the 

 other (the Elephant) has a brain of the enormous weight of 3370 gr. Max Weber says 

 that the former reminds us of the Tertiary mammals, which Marsh has shown to have 

 remarkably small brains, and he expresses the opinion (p. 6) that an animal with such a 

 relatively small brain could have held its own in the struggle for existence only by its 

 safe mode of life. It is of some significance in this connection that the Hippopotamus 

 shows in other parts of its anatomy indications of a very primitive type f. It seems not 

 improbable that in the case of the Hippopotamus and also of OnjcteropmX we have 

 two "lonely creatures" who have become specialized, but only slightly removed from 

 the primitive parent stock. They have early taken to eminently safe modes of life, and, 

 by avoiding the fierce struggle for existence which "weeds out" most mammals that 

 fail to keep pace with the rapid pallial growth, they have managed to linger on in spite 

 of their inferior pallial equipment. The marvel is not that there should remain only 

 solitary examples of these forms, but that even these few representatives of such stujjid 

 creatiu-es should have escaped the fate of the imbecile Glyptodou. 



To the student of brain-anatomy the name which the Du.tchmen of the Cape have 

 o-iven to Orycteropus may not seem so singularly inapproj)riate as it is generally supposed 

 to be ; for in this simple and archaic " Earth- Pig " he may find an exceedingly early 

 offshoot from the root-stock of the Ungulata or Condylarthra. 



In Pouchet's memoir, to which we have so often referred, a doubt is expressed as to 

 whether MaGrotherimn should not be included in the family of Aard-varks. Most 

 observers, however, suggested an analogy between Ilanis and Macrothcrimn, until it was 

 shown that the latter possessed vertebrae and teeth such as we find in a Perissodactyle 

 TJno'ulate §. But to this Oldfield Thomas adds : — " One could not dare to suggest that the 

 ancestors of J/«/m'5 or Orycteropus were to be sought in that direction" 1]. It would 

 unquestionably be absurd to look for the ancestor of Orycteropus among the Perisso- 



* Max "Weber, " Over bet Eeiseugewigt dcr Zoogdieren," Koninklijke Akademie van Wetenschapioen te 

 Amsterdam, October 1S96. t A. S. Woodward, ' Vertebrate Palaeontology,' p. 346. 



j M'. K. Parker, 'Mammalian Descent,' p. 97, wrote : " If ever tbere was a generalized type, tbis [the Aard-varkl 

 is one." 



6 II. F. Osborn, • American Naturalist,' 1882, p. 728. 



11 0. Tbomas, op. cii., Proc. Eoyal Soc. vol. sh-ii. (1890) p. 248. 



