124 -4A^ INTRODUCTION TO ZOOLOGY. 



lizard, frog, mikI newt; lierriiitr, minnow, eel, sole, 

 smd cod ; oyster, cockle, snail ; buttei'fly, cockroach, 

 bee, and aut ; earth-worm, leech, and so on. Make 

 sure which of the great groups of the animal king- 

 dom they belong to, as may be done with the help 

 of this little manual. Ascertain the order, genus and 

 species by reference to some larger work, and then 

 write down all in neat order. For an example of the 

 way in which the beginner should write down infor- 

 mation regarding the place of any animal in classifica- 

 tion, see pp. 302, 804'. 



Note. — The necessity of mastering the difierent Classifica- 

 tions of the animal kingdom given by different authors is one of 

 the chief difficulties that trouble the beginner in Zoology. The 

 student should therefore endeavour to form, and to keep con- 

 stantly in mind, a clear idea of the way in which classifications 

 are made, and of the purpose for which they are made. Place 

 in classification is, as will easily be understood, simplj' a con- 

 cise way of stating the degree of resemblance, near or remote, 

 which the various members of the animal kingdom bear to 

 one another : thus, animals that are almost exactly alike be- 

 long to the same species, and animals that are somewhat alike 

 may belong to the same genus, family, order, class, or 

 phylum, the resemblance becoming more and more remote 

 in the upward order of these divisions. The place of any 

 given kind of animal in classification depends, therefore, on 

 the individual judgment of the writer as to its degree of re- 

 semblance with other forms. Hence there may be consider- 

 able differences between classifications made at the same 

 period, and by writers who are' in possession of the same 

 facts ; and the reader may find that in one part of the animal 

 kingdom the classification of one author best commends itself 

 to his judgment, and in another part of it that of another. 



