4i-ii MR. A. MUEEAY ON THE GEOGBAPHICAL RELATIONS OF 



South- African peculiar forms and a closely allied form in Patagonia. 

 Any doubt, however, that I might feel vanishes when I find 

 other African forms or their representatives in Patagonia. In 

 the Straits of Magellan has been found Agrius fallaciosus, a 

 hunting carnivorous beetle, an undoubted relative of the South- 

 African Manticora ; and although cavils might be made against 

 it on the score of the occurrence of one or two other allied forms 

 in the continuation of the Andes in North America, (Amblycheila 

 and Omus), we have another stronger case still in the presence of 

 the Rhea or South-American Ostrich. It could not be cast on 

 the Patagonian shores by flotsam or jetsam, it could not fly over 

 the intervening ocean ; in fact, it is as strong a case implying 

 actual continuity of soil as could be made up .were one intention- 

 ally to try to contrive one. The concurrence of these three settles 

 the point of their each being genuine instances of the presence of 

 a South- African element only to be accounted for by continuity. 

 The question then comes to be, Where and when did this continuity 

 exist ? As to the when, it seems clear that it must have been 

 prior to the appearance of the Pampas and the plains of Patagonia 

 above water. The specimens oi Eucraniwm have all been obtained, 

 not on the desert-plains or on their margin near the sea, but on 

 the other inland side of these deserts at the base of the eastern 

 side of the Andes, in the deserts of Cordova, in the neighbourhood 

 of Mendoza. Both the African Scarahceus and its Patagonian 

 representative are desert insects, and all Patagonia between the 

 sea and the mountains is apparently sufficiently fitted for it ; so 

 that if it had arrived from Africa after the laud had assumed its 

 present configuration, it ought to have been found on the coast 

 and on the plains rather than beyond them on the now dry shores 

 of this ancient sea-bottom. I infer that it was there before the 

 sea-bottom emerged, and has not yet spread far from the spot it 

 occupied or escaped to on the occasion of that event. The rea- 

 son why it has remained thus stationary, and not gone back as 

 soon as it had the power, by the reappearance of dry land, into 

 its former ground may be that its constitution had undergone a 

 change when its conditions of life were altered. Perhaps until 

 then it was a mere Pachysoma, as at the Cape of Grood Hope, but 

 under the new conditions changed into Mucranium ; or it may 

 be that in the struggle to obtain a footing on the reappearing land 

 it was distanced by other species more speedy in their invasive 

 movements or better suited to the locality. 



