Miscellaneous. 353 



most perfect oval. The bones of the hind feet are proportionably 

 longer, although less strong ; lastly, its form is much more slender 

 than that of the other Anourous Batracians, and may belong as well 

 to the Frogs properly so called as to the Tree-frogs (Hijla), which 

 difFer from the former only in the extremity of each of thtjir toes, 

 which is enlarged and rounded into a kind of viscous swelling. But, 

 as may be imagined, this character has not been preserved. ITie 

 Rana aquensis has preserved a portion of its skin ; there is scarcely 

 any part but the feet which has been deprived of it, and these are 

 represented by the bones which form their skeleton. As may be 

 judged by its dimensions, this fossil frog is small, and its form is far 

 from corresponding to the idea which we may form of the tertiary 

 fauna of Aix, if we imagine it among the palm-trees, the crocodiles 

 and other animals which have left their remains in the gypsiferous 

 marls. 



It is well known, that when the discovery of a diurnal lepidopterous 

 insect in the same formation was announced to the Entomological So- 

 ciety of Paris, M. Boisduval, one of the most celebrated entomologists 

 in Europe, considered the fact as so novel, that he would not credit it 

 until he had examined the specimen. As this discovery has passed, 

 we may say, unnoticed, I shall be pardoned for entering into some 

 details on the almost miraculous occurrence which enabled M. Bois- 

 duval not only to recognise the genus to which this butterfly be- 

 longed, but also to determine its species with the greatest ease. As the 

 opinion of this naturalist perfectly agrees with the ideas which I have 

 previously entertained and published on the probable temperature of 

 the globe at the period of the deposit of the gypsums of Aix, I can- 

 not resist supporting my opinion by such an authority, especially as 

 M. de Serres (Geognosie des Terrains Tertiaires, p. 220, &c.) states 

 that the genera of fossil insects of that locality are mostly identical 

 with those which now inhabit Provence and more southern climates, 

 as Sicily and Calabria ; and as M. Boue (Guide, ii. p. 286) says that 

 it is well-known that the fossil plants and fishes of Aix are most nearly 

 related to the vegetables and marine fishes of Provence, whilst it has 

 been proved that the gypsiferous marls of Aix are essentially of a la- 

 custrine origin, and that no maritime plant or animal has ever been 

 discovered there. Mr. Curtis (Edinburgh New Phil. Journal, Oct. 

 1829) in the same manner refers all the specimens from Aix to still' 

 existing forms. Now as the gypsums of Aix are inferior to the ma- 

 rine molasses of the central beds, containing animals the greater part 

 of whose genera only live in the tropical regions, the occurrence in 

 a lower stratum of species still existing in the country or in the ad- 

 joining countries, established a fact of anomalous distribution, and a 

 contradiction, not only to almost all known facts, but also to the 

 presence in the same stratum of crocodiles, palm-trees, and other 

 species of warm climates. We must therefore consider the conclu- 

 sions advanced by the naturalists whom we have cited as the result 

 of erroneous determinations, into which the specialty of M. Boisdu- 

 val has prevented his falling. That entomologist discovers, " that 

 the most common species of insects of the gypsiferous beds of Aix 



Ann. ^ Mag. N, Hist. Vol. xvi. 2 C 



