THE BliAIX IN THE EDENTATA. 279 



writers even suggest tlieir separation as " Paratheria." Wortman's liypotlicsis brings 

 the Edentata into intimate relationship with the o'dinary Eutlieria, and is quite fatal to 

 the Pavatherian idea. 



The anatomical features of the two Old-World families, the scaly Pangolins (the 

 habitat of which fringes the Asiatic continent from the Ethiopian I'egion in the wesc to 

 the islands at the extreme south-east) and the Ethiopian Onjcleropus (the pig-like 

 appearance of which suggested the name Aai-d-vark, which the Dutchmen of the Cape 

 apply to it), probably differ the one from the other and each from the American forms 

 as widely as their geographical distrilmtion, and concerning tlieir ancestry palaeontology 

 has not revealed much. The present state of our knowledge, or lack of knowledge, of 

 the affinities of the Pangolins and the Aard-varks has been aptly and forcibly expressed 

 by Oldtield Thomas. Writing of Orycteropus he says *: — 



" Although called an Edentate, it has always been recognized as possessing many 

 characters exceedingly different from those of the typical American meml)ers of the 

 order. It has been placed with them rather on account of the inconvenience of forming 

 a sj)ecial order for its reception than because of its real relationship to them. Now, as 

 they are altogether toothless or else bomodont and raonophyodont (apart from the 

 remarkable exception of Tatusla), it seems more than ever incorrect to unite with them 

 the solitary member of the TubuUdentata, toothed, heterodont, and diphyodout, and 

 differing from them in addition by its placentation, the anatomy of its reproductive 

 organs, the minute structure of its teeth, and the general characters of its skeleton. 



" But if Orycteropus is not genetically a near relation of the Edentates, we are wholly in 

 the dark as to what other mammals it is allied to, and I think it would be premature to 

 hazard a guess on the subject. Whether even it has any special connection with ITanis 

 is a point about which there is the greatest doubt, and unfortunately we are as yet 

 absolutely Avithout any palaeontological knowledge of the extinct allies of either. 

 Maci'otherinm even, usually supposed from tlie structure of its phalangeal bones to be 

 related to Munis, has been lately proved to have the teeth and vertebra? of a Perisso- 

 dactyle Ungulate, and one would not dare to suggest that the ancestors of Maitis or 

 Orycteropus were to be sought in that direction. Lastly, as tlie numerous fossil 

 American Edentates do not show the slightest tendency to an approximation towards 

 the Old- World forms, we are furnished with an additional reason for insisting on the 

 radical distinctness of the latter, whose phylogeny must therefore remain for the j)resent 

 one of the many imsolved zoological problems." 



I have quoted these conclusions at some length because they summarize so admirably 

 our present state of ignorance of the interrelationships of the Edentata as a grou^). Nor 

 is our knowledge of the relationsliip of the group to the other Mammalia on a more 

 satisfactory basis. It is, therefore, strange that so little has hitherto been done to call 

 in the evidence which the nervous system, and especially the brain, affords to help to 

 unravel this perplexing tangle of relationships. Eor it is hardly conceivable that the 

 master-organ which presides over the activities of the whole body, and is responsive to 



* Oldfield Thomas. ' A Milk Dentition in Ori/ctei-ojnis,' Proceedings of the lloyal Society, vol. xlvii. (1890) p. 248. 



39* 



