1882.] PROF. W. H. FLOWER ON THE EDENTATA. 365 



by the disappearance of the foetal villi at the two poles of the ovum ; 

 while the small size of the umbilical vesicle indicates that it is not, 

 like the zonary placenta of the Carnivora, directly derived from 

 a type with both allantoic and umbilical vascularization of the 

 chorion. 



Although palaeontology has revealed the existence of a vast 

 number of the Edentates by which the New World was tenanted in 

 the Pleistocene age, and has given us a more perfect idea of their 

 characters than is known of most other extinct forms, unfortu- 

 nately the history of the group throughout the period of the true 

 Tertiaries is at present almost a blank. The presence of a large 

 species probably allied to Manis in the Siwalik fauna is indicated by 

 a single phalanx, described and figured by Lydekker under the name 

 of M. sindiensis. No animals, attributed with any certainty to the 

 Edentata, are known of Eocene age. The few scattered and imperfect 

 remains of supposed Edentates, Macrotherium and Anci/lotkeriiun, 

 of the European later Miocene formations, and the similarly imperfect 

 and as yet not fully described bones of Moropus and Morotherium of 

 corresponding ages in North America, indicate that animiils existed 

 at that time of large size, presenting characters in some respects 

 allied to the recent members of the order, but in others so different 

 that they cannot be placed in any of the existing families. Macro- 

 therium, for instance, appears to have limb-characters which ally it 

 to the Ungulates. As far as can be surmised at present, the 

 affinities of these early forms were rather with the existing members 

 which survive in their own part of the world, than with those of a 

 different hemisphere. Macrotherium certainly appears to present 

 more resemblance to Manis than to the American Edentates. The first 

 fragments of it which were found were attributed by Cuvier to a 

 •' Pangolin gi(/antesque." But some evidence has since been found 

 in favour of its having possessed teeth. So far this is quite what 

 might be expected ; but it certainly throws very little light either 

 upon the mutual relations of the existing forms, the steps by which the 

 present state of things has been brought about, or, what would be still 

 more interesting, their affinities with mammals of other groups. The 

 tabular form (see p. 3G6) into which the result of these inquiries have 

 been thrown will show what I conceive to be the relationship of the 

 existing forms ; but it also shows the great deficiency of our knowledge 

 of the group in past ages. 



The general conclusions to which a study of this group have led me 

 may be summed up as follows : — All the American Edentates at 

 present known, however diversified in form and habits, belong to a 

 common stock. The Bradypodidce, Megaiheriidce, and Myrmeco- 

 phagidcE are closely allied, the modifications seen in the existing 

 families relating to food and manner of life. The ancestral forms 

 may have been omnivorous, like the present Armadillos, and 

 gradually separated into the purely vegetable and purely animal 

 feeders : from the former are developed the modern Sloths, from the 

 latter the Anteaters. The Armadillos are another modification of 

 the same type, retaining some more generalized characters, as those 



