594. SUPPLEMENT ON INFUSORIA. 
should come near the planaria. The true vorticellae we have 
seen to be polypi. Finally, the genera gonium, proteus, vol- 
vox and monads, if they can be certainly regarded as animals, 
ought, in the opinion of M. de Blainville, to form a distinct 
type, to which he gives the names of amorpha, and agastraria, 
which are intended to express that they have no determinate 
form, and that the external envelope does not turn into or form 
a stomach, as in all true animals. 
Though many first rate naturalists, such as Leuwenhoek, 
and Spallanzani, have occupied themselves with the infusoria, 
itis much to be wished that such labours were renewed with 
juster views, and more scientific exactitude of observation. 
Many things, no doubt, would be found to require rectifica- 
tion, and the result would be important, not only to zoology, 
but to general physiology. Many authors, admitting too ge- 
nerally that these animals are born in vegetable or animal in- 
fusions, have taken occasion from this position to maintain 
the doctrine of spontaneous generation, and several other 
notions, more or less erroneous. From some remarks on the 
last of the infusoria, the generation from spontaneous scission 
in the parent, in whose body gemmules might be formed, has 
been also admitted. This from analogy is more probable; but 
it would be well, if possible, to ascertain that it were true. 
The greatest care should be taken in observation to avoid the 
errors which the instrument we are forced to use may lead us 
into. 
Erratum in title of third order of Polypi. 
For polypi polypiferi, read polypi with polyparia. 
