Reviews — Prof. A. Gaudry — The Evolution of Mammalia. 221 



made up of spiciiles. Fig. ct is a spicule of S. flimatilis as seen 

 under a |-incli objective. I do not wish it to be inferred that the 

 tuberculation of the fossil spicules is as plainly shown — it is shown, 

 and that is all. 



I do not know that the occurrence of a fossil freshwater sponge 

 in the British area has been recorded before — and I thought it 

 might be interesting to make a note of it now. I have no doubt 

 a careful search would be repaid by the discovery of specimens in 

 which the orderly arrangement of the spicules is preserved. Should 

 I have an opportunity of doing so, some day I will look for them ; if 

 not, some one else may think it worth while to do so. Meantime, as 

 I suppose the sponge must have a name — although I am almost 

 afraid to suggest one, lest it should already have been noticed and 

 named — I propose to call it Spongilla PurbecJcensis. 



laiB'VIE^WS. 



I. — The Evolution of the Teetiart Mammalia. Les Enchaine- 

 ments du Monde Animal dans les temps Geologiques Mammiferes 

 Tertiaires. Par Prof. Albert Gaudry. Eoyal 8vo. pp. 296, avec 

 312 gravures dans le texte. (Paris : Libraire F. Savy, 1878.) 



THE general tendency of modern thought among scientific men 

 as regards the succession of animal life on the Earth has for the 

 last twenty years flowed in an almost uninterrupted current, not 

 always by the same channels, but biassed by the same inclination, 

 towards the prevailing doctrine of Evolution. 



Indeed, whether we turn to the East or to the West, we are 

 forcibly struck by the cosmopolitan nature of scientific opinion in 

 this respect. Marsh and Cope in America, Darwin, Huxley, and 

 Parker, in England, Gaudry in France, Haeckel in Germany, Dohrn 

 in Naples, are all directing our ideas in the same course. Even 

 Prof Owen, whose early researches on Homologies, like those of 

 Linnaeus in classification, were the advance-guard of the army of 

 Evolutionary ideas, has of late adopted the legitimate consequences 

 of the Philosophy of Evolution, by tracing the descent of some 

 existing types of life. 



These views must not, however, be classed by the reader with those 

 chimerical speculations in which the earlier naturalists indulged, 

 at the beginning of this century; more frequently they are the 

 genuine outcomings of laborious research, often carried on under 

 great difficulties, by men whose minds had been previously trained 



