ON ZOOPHYTES. San 
animals of pretty small dimensions, led to the study of ani- 
mals still smaller, to which the name of microscopic has been 
given. Leuwenhoék and Hartsoéker led the way, but were 
ably followed by Hill, Resel, and others, who considerably 
augmented the number of discoveries in this kind. The dif- 
ficulty of observation, and the want of proper principles to 
guide most of the observers, prevented those animals from 
being sufficiently known, to justify systematic writers in as- 
sembling them in a single group, or even uniting them to the 
zoophytes. All subsequent zoologists left them in the same 
state, just as if the degree of size was of necessity in relation 
with the degree of organization. 
The first systematic author in which we find the micro- 
scopic animals arranged, appears to be Hill. As, however, 
he did not admit the system of subdivision founded upon 
Aristotle, and has no class under the name of zoophytes, it 
is not easy to analyze his labours. The animals to which the 
most recent zoologists give this name, are placed by this 
author in sections exceedingly remote from each other. The 
infusoria, under the name of anzmalcule, are placed altogether 
at the commencement of the animal kingdom. It would be 
equally superfluous and disagreeable to follow him through his 
groups, and to repeat his learned, but very cacophonous ap- 
pellations. It is sufficient to remark, that in his system, or 
no system, the meduse, actiniz, hydre, and asteriz, are in 
the same section with the naked mollusca, and that the 
setigerous annelida are between the insects properly so called, 
and the amphibia, vertebrated animals. 
- The work of Pallas on the zoophytes, may be considered 
as one of the most classic, and the best executed which we 
possess in zoology. He does not, however, by any means 
treat of all the animals now comprehended under the name 
of zoophytes; nor, indeed, are scarcely any of the animals 
