THE 0HIE1 COLUOl'TEROUS FAUNAE. 



1,3 



trated to the axis of the Cordillera in a similar manner to what 

 now happens in the southern part of the same great range." 



There seems no reason to doubt that Patagonia and Chili were 

 both supplied with their present faunas and floras from the main 

 microtypal stock on the Andes. It is natural that from them the 

 newly exposed sea-bottoms should have been peopled as they ap- 

 peared, and quite in accordance with this that the stock flowing 

 off to the right hand and the left should, while retaining a com- 

 mon character, have each respectively minor peculiarities. This 

 is what we should expect, and this is what we find. In both we 

 find the same forms of microtypal Carabidag, Cnemacanthus, Har- 

 palus, Antarctia, &c, the same modifications of Heteromera, as 

 Nyctelia, Cardiagenias, Praocis, &c. ; and in both the fauna, as a 

 whole, is remarkably scanty. 



In Patagonia, however, there occur one or two forms whose 

 presence it is not easy to account for. The genus Eucranium 

 occurs, not on the desert-plains between the mountains and the 

 sea, but at Mendoza, at the foot of the eastern flank of the Andes, 

 where the plains begin to rise into the desert base of the moun- 

 tains ; for notwithstanding the advantage of water from their 

 snowy peaks, the coarser shingle at the base of the mountains 

 maintains its sterility equally with that of the less-watered finer 

 shingle at a greater distance from them. Now Eucranium is un- 

 doubtedly the representative of the Caffrarian genus Pacliysoma, 

 which is one of the Ateuchidae, or pill-rolling beetles of Africa and 

 India, the ancient Scarabceus of the Egyptians ; and if this were 

 a solitary case, I might perhaps have tried to get over it by 

 arguing that although the Scarabceus is certainly an Indo-African 

 form (being found both in India and Africa, and in prepondera- 

 ting numbers in Africa and all over Africa), it might yet have 

 originally been microtypal because it is found in the Mediterra- 

 nean district, not only in Egypt, Algeria, and Barbary, but also 

 in Italy, Greece, &c, and from thence might have extended into 

 Africa. But against this is the fact that At euchus is not found in 

 Heer's lists of Miocene species, although Gymnopleurus, another 

 pill-rolling beetle, whose distribution is similar to that of Ateuchus, 

 is recorded there. The latter fact may be only an earlier instance 

 of what has taken place in Ateuchus, or it may refer to some more 

 ancient state of things ; for all Coleoptera have no doubt been 

 originally connected : but the connexion of Ateuchus with Europe 

 is not the immediate point ; it is the connexion between one of its 



