354 THE NATURAL HISTORY REVIEW. 



of the genera, which, with the help of the tables of geographical and 

 geological distribution appended to the sections on the relations of 

 the classes to space and time, produces a remarkably clear and com- 

 prehensive view of the highest results of systematic Zoology. 



In the section treating of the part played by the different classes, 

 or rather by their members in the general ceconomy of nature, we find 

 briefly indicated the principal modes in which each animal type 

 reacts upon its fellows, whether by preying upon them or by being 

 preyed upon, and also the effects produced in the grander operations 

 of nature, connected with the formation of new geological beds. 

 After this brief and imperfect account of the general treatment of 

 the subject adopted by Professor Bronn, we may now proceed to 

 indicate the general classification which has been followed by him in 

 the present work. 



Professor Bronn distinguishes five sub-kingdoms of Animals, which 

 he calls AmorpTiozoa, (= Protozoa), Actinozoa (=Sadiata), Mala- 

 cozoa, Entomozoa and Spondylozoa. The characters of these five 

 primary groups are brought together at the end of his general intro- 

 duction, (Vol I. p. 9), in a table which will well repay a close exami- 

 nation, as it displays the agreements and discrepancies presented 

 by all those portions of the organism to which naturalists have 

 referred for the characters of their primary classification, and at the 

 same time shows the difficulty of adopting any one system of organs, 

 or set of characters for the discrimination of the leading types of 

 animal structure. Of all single characters, the nature of the nervous 

 system corresponds most closely, as is well known, with the general 

 results of systematic investigations, but even this is liable to excep- 

 tions ; and Professor Bronn's table shows clearly that embryological 

 characters cannot be applied to this purpose on the scale in which 

 they have been employed by some writers. 



The sequence of the sub-kingdoms in the ascending or descending 

 scale, which we are forced to adopt in treating of the animal kingdom 

 as a whole, is perhaps in the present day, a matter of little con- 

 sequence. Professor Bronn places the Entomozoa, (or Annulosa) 

 above the Malacozoa, evidently guided by the fact that in them as a 

 rule the organic systems of animal life predominate, whilst in the 

 three lower groups, as indicated by him, we find a predominance of 

 the vegetative functions. It may, however, be questioned whether, 

 although the great majority of the Entomozoa may present more 

 highly animal characters than the majority of the Mollusca, the 



