Some Observations on Amceba proteus. 199 
but more concentrated than that found in A. proteus Y, from which it 
differs chiefly in the number of its nuclei. 
With regard to the crystals contained by these amcebee, two types may 
be recognised as predominating, both apparently based upon the octahedral 
form. Leidy,! Stolc,? and Vonwiller*® have shown these crystals well and, 
with Schubotz and others, have discussed their chemical or probable chemical 
composition. 
The characteristic crystal of A. protews X measures typically 6p x35 p to 
8X4, is bipyramidal and usually doubly truncated. Occasionally crystal 
aggregates are met with similar to those figured by H. J. Carter,* although 
not quite so perfect in form. Small crystals, if present at all, are few in 
number, sometimes regular octahedrons at other times resembling the larger 
crystals. In A. proteus Y there is a mixture in which the large crystal of 
A. proteus X predominates over complete, medium, and small crystals of 
apparently similar construction in inverse proportion as the condition of the 
amoeba passes from the YX to the Z end of the series; the number of large 
crystals in A. proteus Z being practically zero. The crystals found in 
A. proteus Z are figured by Vonwiller; always complete bipyramids. They 
vary in number; at one time very numerous, giving the well-known grey- 
black shade to the amceba, and at other times detected with difficulty, so few 
are they among the highly granular contents of this “ type” of amceba. 
The other inclusions — glistening bodies, staining or non-staining 
spherules, parasites, so-called embryons, etc.—are not constant. 
The nucleus is a point open to discussion more than any other. Is the 
nucleus the same in all the amcebe, to be classed as A. proteus? and when 
a difference in appearance is noted, is the amceba immediately to receive 
a new specific name? or, if it be admitted that there is a difference in 
the nucleus of the different members of the group, is it a radical difference 
or only a change brought about by environment, change of season, or by 
some phase in the life-history of the organism, a pathological condition 
or some physiological change in constitution? Any or all of these causes 
may be held accountable for much that is met with in the nucleus of 
A. proteus. 
Without entering into the details of the nuclear constitution of the 
amocebee under discussion, I wish simply to record observations, not deductions. 
Taking the nucleus of each “type”—A. proteus X is uninucleate—only twice 
1 Leidy, loc. ext. 
2 Stole, Korenonozci, 1899. 
3 Vonwiller, Arch. fiir Protist., vol. xxviii, 1913. 
“ H. d. Carter, A.N.H., vol. xii., 1863. 
