II2 ANIMAL ACTIVITIES. 
Grass- 
hopper. Spider, | Lithobius.| Shrimp. 
Bilateral ? 
Are appendages 
jointed ? 
Wings, antenne, 
legs, and swim- 
merets. 
Divisions of 
body. 
Respiration. 
Locomotion. 
animal kingdom. Sub-kingdoms are divided into 
Classes, classes into Orders, orders into Families, 
families into Genera, genera into Species. Thus the 
milkweed-butterfly belongs to the sub-kingdom Ar- 
thropoda, the class Insecta, the order Lepidoptera, the 
family Nymphalide, the genus Danais, and the species 
Archippus. Such an arrangement must be to some 
extent artificial, because animals are not run in molds 
like bullets or stamped with dies like coins. Never- 
theless, the great number of animal forms compels us 
to adopt some scheme of classification to prevent con- 
fusion. 
Examining our notes concerning the Arthropoda, 
we find that all are bilateral, all have an exoskeleton, 
segmented bodies, and jointed appendages. These 
