550 THE AMERICAN NATURALIST. 
round which the Stabchen never form a mantle. Blochmann 
groups these forms under P. palustris. Other forms Bloch- 
mann unites under the provisional species, P. greefi, character- 
ized by the almost complete absence of the granules, and by 
the small number of Glanzkórper, which are always surrounded 
by a thick coating of Stabchen. The peculiar habitus assumed 
at times, absence of sand in the body, absence of Stabchen, 
presence of the crystals, are the distinguishing characteristics 
of my species against the related forms, P. palustris, P. vil- 
losa, P. greefi. 
The habitus in rhizopods, however, is undoubtedly a most 
inconstant feature, readily affected by the individual environ- 
ment, as may be learned from P. carolinensis itself. The 
interesting observations of Verworn (Allgemeine Physiologie, 
p. 190) on the change of shape in amcebas, through the A. ro- 
teus, A. limax, and A. radiosa condition, likewise indicate this. 
And it seems probable, from the diverse forms of Pelomyxa, 
that Blochmann (loc. cit.) has found that the cytoplasmic inclu- 
sions, even the characteristic Glanzkórper, are all inconstant, 
and are to be looked on as the outcome of the individual envi- 
ronment. A greater familiarity with the four above-mentioned 
forms may thus show that they all belong to. a single species. 
UNIVERSITY OF NORTH CAROLINA, 
December 18, 1899. 
