318 Bihliog^-apliical Notices. 



]iad been variable in tlie grade immediately below. He must 

 also realize that in the interval between these impulses some 

 minor characters in the families similarly acquired fixity ia 

 iheir prime, until old age and extinction approached. The 

 .aeneral conclusion is, that if the unknown influence -which 

 Cope has termed " bathmic force ^^ were able to act without 

 a succession of checks from the environment and Natural 

 Selection, animals would form much more symmetrical 

 (groups than we actually find, and their ultimate grades would 

 display still more instances of numerical fixity in multiple 

 parts than can be observed under existing circumstances. 



This result almost tempts a ])ala3ontologist to risk the 

 ])itialls of reasoning from analogy and to compare organic 

 evolution with some purely physical processes. It has already 

 been pointed out more than once that the initial stages of 

 animal races resemble the nascent states of chemical elements 

 in their particular intensity of vigour and unwonted suscepti- 

 bility to influence ; while Cope himself has hinted that the 

 " expression points " in the evolution of races may, perhaps, 

 be compared with the phenomena of latent heat in the inorganic 

 Avorld. It now seems reasonable to add that each " phylum/' 

 or separate chain of life, bears a striking resemblance to a 

 crystal of some inorganic substance which has been disturbed 

 by impurities during its growth, and has thus been fashioned 

 Avith unequal faces, or even turned partly into a mere con- 

 cretion. In the case of a crystal the inherent forces act 

 solely upon molecules of the crystalline substance itself, 

 collecting them and striving, even in a disturbing environment, 

 to arrange them in a fixed geometrical shape. In the case of 

 an organic phylum, the inherent forces of the colloid germ- 

 plasm act upon a consecutive series of temporary outgrowths 

 or excrescences of colloid substance (the successive individual 

 bodies or "son:ata''), struggling not for geometrically 

 arranged boundaries, but towards various other symmetries 

 and a fixity in number of multiple parts. Palaeontology thus 

 contributes to Biology by placing the oft-repeated comparison 

 cf life with crystallization in an entirely new light. 



BIBLIOGRAPHICAL NOTICES. 

 A Descriptive CUaJor/Kc of the Tertiary Verfelrata of the Faifihn, 

 Egypt. By Chakles AYilliam Andrews, D.Sc. Pp. 5sxvii-f-'324, 

 l)ls. 2Q, and text-figures, London : Printed bv Order of the 

 Trustees of the British Museum. lUOG. Price 'Sbs. 



Dr. Andrews is a zoologist in the widest sense of the term, and 

 hence it is that this bulky volume is soinethuig more than a mere 



