e 
258 THE AMERICAN NATURALIST. 
and created for the organism a new genus and a new species. 
He saw, however, but one individual. I was more fortunate in 
that I found many individuals of the two kinds that I have 
figured. 
It is known that a pseudopodium may turn into a flagellum, 
and, conversely, that a flagellum may turn into a pseudopodium. 
This, together with the fact that these two animals were identical 
in all respects but one, and that they occurred side by side in the 
same drop of water, renders it very probable that they are only 
different conditions of one and the same animal. There seems, 
then, no good reason for creating a new name, and I accordingly 
suggest retaining that used by Leidy, Vampyrella lateritia, even 
though the definition of this species must be somewhat enlarged. 
HARVARD UNIVERSITY, Feb. 5, 1900. 
