INTRODUCTION. xiii 
It will be found by reading the following sketch of the Modern 
System, that the greatest change has taken place in the latter two 
classes. The others remain nearly the same in effect, though their 
distinctions are different, and the classes are not arranged in the 
same order. 
MODERN SYSTEM. 
ACCORDING to Cuvier, all animals are arranged in four great di- 
visions, which are subdivided into classes, and orders, as fol- 
lows : 
DIVISIONS. 
I. VERTEBRATA. l 
2 Aves .... 
. . Six 
Four Classes. Twenty- > 
3 Reptilia . . . 
. Four. 
seven Orders. j 
4 Pisces .... 
Nine 
II. MOLLUSCA. "I 
Six Classes. Fifteen ! 
Orders. | 
j 
III. ARTICULATA. -, 
1 Cephalopoda 
2 Pteropoda . . 
3 Gasteropoda 
4 Acephala . . 
5 Brachiopoda 
6 Cirrhopodes . . 
1 Annelida . 
. . One. 
. . One. 
. . Nine. 
. . Two. 
. . One. 
. . One. 
. Three. 
Four Classes. Twenty- I \ ? r fS Seven, 
fmir Orrlprs I 3 Arachnida .... Two. 
J 4 Insecta Twelve. 
IV. RADIATA. ~) 1 Echinoderma . . . Two. 
I 2 Intestina Two. 
Five Classes. Eleven > 3 Acalepha Two. 
Orders. | 4 Polypi Three. 
J 5 Infusoria Two. 
THE VERTEBRATED ANIMALS 
Have a backbone divided into vertebrae or joints, whence they take 
their name. They have also separate senses for hearing, seeing, tast- 
ing, smelling, and feeling ; a distinct head, with a mouth opening by 
two horizontal jaws ; a muscular heart, and red blood. The four 
classes of Vertebrata and their orders are as follows. 
I. THE MAMMALIA are all furnished with mammae, or teats, through 
which they give milk to their young, which they bring forth 
alive. They have warm blood, which circulates from the 
heart though the lungs, and returns to the heart before it 
passes through the body. Their skins are naked, or co- 
vered with wool or hair, and their mouths are generally 
