4 SPHERE AND FUNDAMENTAL 



consider that wherever any one stratum of the earth has 

 been well explored, the number of species discovered has 

 not fallen below that of the living species which now inhabit 

 any particular locality of equal extent, and then bear in 

 mind that there is a great number of geological strata, we 

 may anticipate the day when the ascertained fossil species 

 will far exceed the living species.* 



8. These numbers, far from discouraging, should, on the 

 contrary, encourage those who study Natural History. 

 Each new species is, in some respects, a radiating point 

 which throws additional light on all around it ; so that as 

 the picture is enlarged, it at the same time becomes more 

 intelligible to those who are competent to seize its promi- 

 nent traits. 



9. To give a detailed account of each and all of these 

 animals, and to show their relations to each other, is the 

 task of the Naturalist. The number and extent of the vol- 

 umes already published upon the various departments of 

 Natural History show, that only a mere outline of a domain 

 so vast could be fully sketched in an elementary work, and 

 that none but those who make it their special study can be 

 expected to survey its individual parts. 



10. Every well-educated person, however, is expected to 

 have a general acquaintance with the great natural phe- 

 nomena constantly displayed before his eyes. There is a 

 general knowledge of man and the subordinate animals, 

 embracing their structure, races, habits, distribution, mutual 

 relations, &c., which is calculated not only to conduce es- 



* In a separate work, entitled " Nomenclator Zodlogicus^ by L. Agas- 

 siz, the principles of nomenclature are discussed, and a list of the names of 

 genera and families proposed by authors is given. To this work those are 

 referred who may desire to become more familiar with nomenclature, and 

 to know in detail the genera and families in each class of the Animal 

 Kingdom. 



