210 ON SYSTEMATIC ZOOLOGY. 
sporting, as it were, with every thing like regularity. 
But this, I apprehend, is the consequence of a too rapid 
glance ; since nature, so far from forgetting order, has, 
at the commencement of her work, in these imperfect 
animals, given us a sketch of the five different forms 
which she intended afterwards to adopt for the whole 
animal kingdom. In the soft, mucous, sluggish Jntes- 
tina, she has given the outline of the Mollusca. In the 
fleshy living mass which surrounds the bony and hollow 
axis of the Polypi natantes, she has sketched a verte- 
brated animal. In the crustaceous covering of the 
living mass, and the structure, more or less ar entered! 
of ing Polypi vaginati, we trace the form of the bie 
losa ; while the radiated forms of the Rotifera, and the 
simple structure.of the Polypi rudes, may, in general, 
remind us of the Radiata.” * Assuming, therefore, that 
the Acrita, as here defined, is really a natural group, 
and allowing the analogies for the sake of explaining 
the principle, we see a complete exemplification of our 
author’s meaning in one of the primary groups of the 
animal kingdom. We shall now cite another instance 
given by him in one of the smallest groups, namely, 
the typical group of the genus Scarabaeus (Gymnopleurus, 
Ill.). In speaking of this, our author thus expresses 
himself : —‘‘ I have thus attempted to find characters 
for the natural groups which appear on disposing the 
Gymnopleuri according to their affinities ; but the proper 
method of considering them all is, as referable to one 
or other of forms which may be expressed by the five 
following species: —1. Azureus; 2. Flagellatus; 3. 
Cerulescens; 4. Kenigii; 5. Miliaris. In almost 
every group which has been set before the reader, he 
must have perceived that one of the five minor groups, 
into which it is resolvable, bears a resemblance to all the 
rest ; or, more strictly speaking, consists of types which 
represent those of each of the four other groups, toge- 
ther with a type peculiar to itself. This is visible in 
the compositien of the Acrita among the divisions of the: 
* Hor. Ent. 223, 
