290 Bibliographical Notice. 



extended to twelve volumes, to which it is attached ; and we venture 

 to recommend its re-issue in a separate form. 



In the first chapter of this introductory essay, Professor Agassiz 

 enters at length into the fundamental relations of animals to one an- 

 other and to the world in which they live. He insists that " classi- 

 fication rests upon too narrow a foundation, when it is chiefly based 

 on structure." "Animals," he most truly observes, "are linked 

 together as closely by their mode of development, by their relative 

 standing in their respective classes, by the order in which they have 

 made their appearance upon earth, by their geographical distribu- 

 tion, and generally by their connexion with the world in which they 

 live, as by their anatomy. AW these relations should, therefore, be 

 fully expressed in a natural classification ; and, though structure 

 furnishes the most direct indication of some of these relations, always 

 appreciable under every circumstance, other considerations should 

 not be neglected which may complete our insight into the general 

 plan of creation." Prof. Agassiz's views on the geographical distri- 

 bution of animals, on the permanency of specific peculiarities, and 

 on the parallelism between the geological succession of animals and 

 the embryonic growth of their living representatives, are particularly 

 worthy of notice. An ardent supporter of the theory of the perma- 

 nency of species, he most emphatically repudiates the * Vestigiarians* 

 and their views, concluding with the proposition, that " Beings do 

 not exist in consequence of the continued agency of physical causes, 

 but have made their appearance upon earth by the immediate inter- 

 vention of the Creator." 



The second chapter treats of the leading groups of the existing 

 system of animals, and gives us the author's views on * types,' * classes,' 

 'orders,' 'families,' * genera,' and * species.' Professor Agassiz repu- 

 diates as 'pedantic' all the other divisions and subdivisions so often 

 employed in Natural History, such as subfamilies, subgenera, and 

 the like. Branches or types, he says, are characterized by the plan 

 of their structure, classes by the manner in which that plan is exe- 

 cuted, orders by the degrees of complication of their structure, 

 families by their form as far as determined by structure, genera by 

 the details of the execution in special parts, and species by the *' rela- 

 tions of individuals to one another and to the world in which they 

 live, as well as by the proportions of their parts, their ornamenta- 

 tion, &c." Yet he allows that " there are other natural divisions 

 which must be acknowledged in a natural zoological system, but 

 these are not to be traced so uniformly as the former ; they are in 

 reality only limitations of the other kinds of divisions." As to 

 species. Professor Agassiz rejects the generally-received notion, that 

 sexual connexion resulting in fertile offspring is a trustworthy evi- 

 dence of specific identity, and enters into this question at some 

 length. As is well known, the Professor is an ardent advocate of 

 the cause of the ' Polygenists' against the 'Monogenists' in their 

 respective theories of the origin of the human race, — holding that 

 man was created in nations, and distributed over the face of the 



