318 PROF. HUXLEY ON THK ALECTOROMORPH.E. [Mav 14, 



Others have the converse distribution ; that is to say, they exist 

 in Austro-Colunibia and over a large part of Arctogsea, but are absent 

 in Australia : — 



PsittacitKB, CeIeomorj)h(e, 



Trogonidce, AmphimorphcB, 



among Birds ; and 



Primates (except Man), Ungulata, 



Carnivora, Edentata, 



among the Mammalia. And it is further remarkable that, among 

 these western annectent Mammalia, there are sundry important fami- 

 lies, such as the Camelida, Cervidce, Tapiridce, Ursidce, Subursidce, 

 and (with one or two exceptions) the Melidce and Mustelidce, which 

 are found both in Austro-Columbia and Asiatic Arctogaea, but are 

 absent in South Africa. 



I am not aware that any important group of birds has the same 

 distribution. 



Among land-animals, a single group of these western annectent 

 Mammalia, the Echimyini, is found only in Austro-Columbia and 

 South Africa. The genus Manatus, among Mammals, and the 

 order Dipnoi, among Fishes, are aquatic animals with a similarly re- 

 markable distribution. I do not know of any exactly corresponding 

 case among Birds ; but I may remark that two most peculiar groups 

 of South African Birds, the Musophagidce and the Struthionidce, 

 come nearer the Austro-Columbian Rhamphastidce and Rheidce than 

 to any other forms. 



The existence of these western annectent groups, now in many 

 cases confined to the southern parts of the New and Old Worlds, 

 and separated by thousands of miles of sea, is utterly unintelligible 

 and inexplicable without the aid of palaeontology, which demon- 

 strates that, in the earlier part of the tertiary epoch. Western and 

 Northern Arctogsea, from Nebraska through Central Europe to the 

 Siwalik Hills, was inhabited by a fauna which, so far as Mammals 

 are concerned, was competent to supply Africa and India with their 

 Apes, their Unfjulata, their Carnivora, and to furnish Austro- 

 Columbia with the Proboscidea, Horses, and Machairodus, which 

 it once possessed, and with its existing Tapirs, and Cameline and 

 Marsupial quadrupeds. 



We may expect a great deal of important information respecting 

 miocene birds from M. Alphonse Milne-Edwards, who has already 

 demonstrated the existence of several species of Flamingos in France 

 during the miocene epoch, and has thus connected the existing dis- 

 tributional areas of these birds, just as the miocene Tapir of Europe 

 connects the Indian and South-American Tapir. 



But, it is very interesting to remark, the European miocene and 

 eocene formations have, as yet, yielded no trace of Armadillos or 

 of Sloths, of Kangaroos, Phalangers, AVombats, Dasyures, Thyla- 

 cines, or Monotremes ; and, so far as existing evidence may be 

 trusted, it is highly probable that the three great distributional pro- 

 vinces of Arctogaea, Austro-Columbia, and Australasia were as dis- 



