DIVISION IV. 
RAIMA T A. 
This division is separated into six classes. 
The animals comprehended in this division, are much more 
simple in their organization than those of the preceding. Dif¬ 
fering widely in form, according to Cuvier, they agree in one 
striking particular, that of having all their members disposed 
around an axis, in two or more rays ; hence the name of the divi¬ 
sion. 
The division has been reduced into six classes •, namely, I. 
Echinodermata. —II. Tunicata.— III. Entozoa. —IV. Ac- 
alepra. — V. Polypi.— VI. Infusoria. 
class x.—echinodermata. 
With a suborbicular body, having a crustaceous covering, 
radiated, devoid of a head, eyes, and articulated feet; mouth 
placed below, simple or multiform ; having compound digestive 
organs ; with exterior tubes or pores for respiration. 
A leading character of this class, consists in the struc¬ 
ture being radiated, both internally and externally. The ani¬ 
mals have orbicular bodies for the most part, with a calcare¬ 
ous or crustaceous envelope or skin. The internal cavity con¬ 
tains the viscera, and a kind of vascular system carries on a 
