'2572 The Zoologist — Apbil, 1871. 



wrong position ; but he did not agree with him in his estimate of the length 

 of time necessary for the operation of great geological changes. Fossil 

 shells, &c., from Solenhofeu were referrible to recent genera, and Prof. 

 Heer had identified the fossil plants of the miocene of Madeira with genera 

 now existing there. Furthermore, it was known that Cardium edule was 

 found in a fossil state in the Aralo-Caspian region and in the Sahara, and 

 he thought the elevation demonstrated by this fact was not opposed to the 

 idea of a corresponding depression in the Atlantic. The great objection to 

 his mind, to the theory of population by atmospheric means, was the 

 remarkable homogeneity of form in the fauna of the various groups. If the 

 fauna were derived from atmospheric agencies there would not be this 

 community of form. As a proof of this he would cite Keeling Island, 

 which has an insect fauna of nineteen species, belonging to almost as many 

 orders. 



Mr. Bates could not consider the argument of the existence of Cardium 

 edule in the Aralo-Caspian basin as of much weight, it not proving the 

 operation of great elevation within a comparatively recent period, the district 

 in question being still eighty-three foot below the sea-level. 



The President said it was impossible with him to overcome the geological 

 difficulty in the way of a supposed former land-connection ; for though he 

 could readily believe in great elevation or depression, either continuous or 

 alternate, yet it was a generally received opinion that the great depths 

 between these islands and the continent of Europe had existed since the 

 secondary period. The example of Keeling Island, as noticed by Mr. 

 Murray, was of little importance, because, being a coral island, it was 

 of very recent date, and, as there was little variety of vegetation, it was 

 impossible for the insects to show great increase ; but, let the island become 

 more elevated, and its fiom more varied, then its few involuntary insect 

 immigrants would each become the nucleus of a group of generic forms. 

 Mr. Murray had not explained the greatest objection to Mr. WoUaston's 

 theory, the wonderful absence in the Atlantic Islands of indigenous mammals 

 and reptiles, which, if the islands be the remnants of a once-existing 

 continent, ought certainly to be represented ; neither did he account for 

 the absence of the apterous groups of bulky European heteromerous 

 beetles, such as Blaps, Pimelia, etc., an absence the more remarkable in the 

 face of the fact that genera, and even species of other families, became 

 apterous in the islands, though they are winged in Europe. 



In connection with the absence of mammals, Mr. Bates alluded to the 

 almost total want of coprophagous beetles, a group very numerous in species 

 in those parts of Europe that approach nearest to the Atlantic islands. — 

 B. WL. 



