298 PROCEEDINGS OF THE ACADEMY OF 



I have already alluded to the great variety of tbe highest or peiitatnerous 

 carnivorous beetles in the Pahenrctic Region. They are extremely abundant 

 in the Nearctic, while the intermediate territory, the Sonoran and Mexican 

 sub-districts, are the head-quarters of the next lower form, the Tenebrionidae, 

 which have the tarsal joints 4 — 5. These give place in the Neotropical to the 

 multitudes of the still lower series, — those with the joints 4 — 4 and 3 — 3, — 

 Tetramera and Trimera. 



The preceding comparisons indicate that an inherent difference between the 

 types of a continent exists at the present time, though the difference is su>)- 

 ordinated to a universal distribution of the higher groups throughout the 

 earth. Has this state of things existed for any long period, or is it a result of 

 different progress in the same group since the human period? This brings us 

 necessarily to a consideration of the truths of palaeontology, especially of the 

 last periods, which have been already urged by Darwin. Thus the present 

 fauna of Australia was preceded in the postpliocene and pliocene by forms 

 possessing similar peculiarities, and belonging to the same classes. That is 

 by herbivorous and carnivorous marsupials and monotremes, and by Varanid 

 Sauria, all of greater size than their predecessors. 



The same fact is well known of the Neotropical region, its present peculiar 

 Edentata having been preceded by giants of the same type in the postpliocene 

 and pliocene. 



In the Nearctic region peculiar existing genera, as Procyon, Alces, Castor, 

 Bos, Sciurus, Arctomys, Lepus, Ovibos, Sorex, Mephitis, Felis, Ursus, Meno- 

 poma, Aspidonectes, Crotalus, are represented by postpliocene fossils, 



Tbe same occurs in the later Pala'arctic formations, where Cervus, Bos, 

 Canis, Mustelidse, Insectivora, Vijiera, Alytcs, Triton, etc.. are allied predeces- 

 sors of existing types. In the Palaeotropical area a wonderful development 

 of Elephas and Gavialis preceded the same types of the present. 



Prior to these faunje another state of things has, however, existed. North 

 America has witnessed a withdrawal of a Neotropical fauna, and the Pala'- 

 arctic the retreat of an Ethiopian type. During the postpliocene in North 

 America, Neotropical genera were to Nearctic as 12 to 29, as the record now 

 stands. In the pliocene beds of Pikeimi (Greece) antelopes, giraffes, rhinoce- 

 ros, hippopotamus, huge manis,* monkeys, monitors, and other genera and 

 species of African relationship are the prevailing forms. 



Still earlier, a strong mingling of Nearctic, and more of Neotropical types, 

 abounded in the Pala?arctic. The genera Chelydra, Andrias, Podocnemis.f 

 Platemys, Caviiform, Psanimorj'ctid and Hesperomys-like Rodentia, Opossums, 

 and Raccoon-like Carnivora. 



We have, then, three important terms from which to derive a theory of the 

 creation : 1, the existing six fauna; bear in many of their parts developmental 

 relations to one another ; 2, they were preceded immediately by faunse similar 

 to them in each case, but more remotely by fauna? like that now next lower. 



On the whole, there can be no doubt of the truth of the generalization, 1st, 

 That the Southern Hemisphere is a geologic stage behind the Northern Hemisphere in 

 progress^ on account (i) of its perfection in types extinct in the Northern, and 

 (2) inferiority in modern types prevalent in the Northern. 



In order, however, to demonstrate this point more fully, let us examine to 

 what extent the higher types exist in the Southern, and lower or ancient in 

 the Northern. 



The Percoid fishes and their allies have Australian and South American 

 representatives in their fresh waters, but they are as mere outliers of the 

 great mass in the Northern Hemisjihere. The higher type of venomous ser- 

 pents (Solenoglypha) occur in both the J3thiopian and Neotropical regions, 

 but they preponderate in the Northern Hemisphere. The higher group of the 



* Aneylotherium, Maerotherium. 



■f-P. bowerbankii {Platemys Ow.) P. 1 se v i s {Emys Owen), ;j 



[Oct. 



