430 Reviews — Prof. Gauclry — Philosophical Palaeontology. 



give a general idea of the coarse followed in the evolution of the 

 animal kingdom from the earliest times to the present, day. 



This progressive advance is compared by the author to the changes 

 passed through in the development of an individual man, and in 

 the successive chapters of his work he considers (1) the multiplica- 

 tion of beings, (2) their differentiation, (3) their increase in size in 

 the course of geological time, (4) the progress of activity, (5) the 

 progress of the perceptive faculties, (6) the progress of intelligence. 



In the chapter dealing with the multiplication of animals, it is 

 asserted that the number of organisms has increased successively 

 from the Cambrian onwards, and that this increase was facilitated 

 by the fact that the earlier forms were more strongly armoured than 

 the later ones, and at the same time were less exposed to attack. 

 That there has been an enormous increase in the forms of animal 

 life is, of course, obvious, but that the fossils of the earlier rocks 

 give any idea of the richness of the contemporary faunas is more 

 than doubtful, since it is to the fact of their well-developed skeletons 

 that these fossils owe their preservation, while doubtless innumerable 

 forms must have existed in which the hard parts were little or not 

 at all developed, and of these scarcely a trace remains. Again, if the 

 earlier types were less exposed to attack, it is difficult to understand 

 why in the greater number, according to the author, the means of 

 defence should have been brought to so high a state of perfection. 



In the chapter on the increase of size in animals, still pursuing 

 the comparison with the life of the individual, it is stated that 

 there has been a gradual advance in this respect from first to 

 last. This, again, hardly seems borne out by the facts, for if we 

 take almost any group of animals we find that though for a time 

 the bulk may have increased, a maximum is arrived at, at different 

 periods in the different classes, after which a diminution sets in. 

 In the Amphibia, for example, this maximum was reached in the 

 Trias, while the largest reptiles were Jurassic. The Mammalia, it 

 is true, having been evolved later in time than any other group of 

 the Yertebrata, may be said truly to have attained their maximum 

 development to-day in the living Cetacea, hugest of all moving 

 creatures that breathe, and it needs but small prophetic wisdom to 

 see the rapid disappearance of these, and, indeed, of all the larger 

 mammals within the next few years, annihilated everywhere by the 

 advance of man the destroyer. Of the larger forms the horse, cow, 

 and sheep will soon alone survive, and even the horse may succumb 

 before the motor-car and the bicycle ! In the invertebrates the same 

 phenomenon may be observed ; for instance, the gigantic Pterygotus 

 of the Silurian and Devonian periods, is unsurpassed in bulk by any 

 recent Crustacean. The later chapters dealing with the progress of 

 the perceptive faculties and of intelligence will meet with fewer 

 objections, but even here the generalizations will not always hold 

 if an attempt be made to apply them to particular cases. 



The pages on the utility of palaeontology to the stratigraphers are 

 perhaps the most interesting in the book, but it seems hard to think 

 that it should be found necessary nowadays to employ elaborate 



