INTRODUCTION. 



Xlll 



important structural and anatomical peculiarities and are 

 united into a single class, AVES (a'vez), which includes 

 all the birds. 



The birds are united with other classes, as the fishes, 

 reptiles, mammals, etc., in being built on the same gen- 

 eral plan, and are regarded as off-shoots of a single 'branch, 

 the VERTEBRATA (ver te bra' ta). Several branches, 

 as vertebrates, arthropods (ar'thr6 podz), etc., spring from 

 the main trwik, or ANIMAL KINGDOM. As will be seen 

 further on, an effort has been made to have these scien- 

 tific terms characteristic. 



A general arrangement of the Animal Kingdom would 

 be tabulated as follows : 



BRANCHES. 



SINGLE CELLED ANIMALS Protoso'a. 



V) 



<t 



o 



Exhibiting a Ra'di 5te structure. 



With several incurrent and j 

 one, or several, excurrent yPonf'Srd. 

 openings. ' 



which serves also as an I Cce len ter a'td. 



With a single incurrent, 



I 



excurrent opening. 



With a single incurrent and \ 

 also a single excurrent > Ech i no derm' a td 

 opening. 



Exhibiting a more 



or less obvious seg' 



mented structure. 



WITHOUT | 

 JOINTED I Not covered by a " mantle." Ver' met. 



LOCOMOTORY f Covere d by a " mantle." Mollus'cd. 



APPENDAGES. J 



\VrTH MOJ!E 



OR LESS 



JOINTED 



LOCOMOTORY 



. APPENDAGES. 



> Skeleton external. 

 Skeleton internal. 



Arthrop'o dd. 

 Ver tebr a'td. 



