244 IEG EISL TD [VoL. XII. 
g. A spherical piece 66m in diameter ; contained a single 
elongated node of the nucleus. 
10. A spherical piece 69 in diameter; contained seven 
nodes of the nucleus. 
Other similar pieces containing one or more nodes of the 
nucleus were seen; some were of course not spherical, but I 
have given the spherical pieces as easier to compute the 
volume. Of larger nucleated pieces there was no lack ; they 
were very numerous, as one would expect. There were, of 
course, numerous unnucleated masses of protoplasm of various 
sizes, but few large pieces. In fact, the majority of the pieces 
below 100m in diameter were unnucleated; but the above list 
shows that a good many of such small pieces contained one or 
more nodes of the nucleus. I did not attempt to ascertain 
what was the proportion of nucleated to unnucleated pieces of 
such small size; but it must have been quite large, perhaps 
one to ten or even more. 
One further remark as to my methods. When any doubt 
existed in my mind as to the presence of parts of the nucleus 
in examples noted, the specimen was killed and stained, 
generally in Schneider’s aceto-carmine, and the actual condi- 
tion of the nucleus thus determined with certainty. This of 
course involved the sacrifice of a great deal of material. 
In consequence of the often curious and asymmetrical shapes 
of the pieces produced by shaking, I expected to obtain valu- 
able results on the teratogeny of the Stentors for comparison 
with the results of Balbiani and Johnson, but I have been 
almost completely disappointed in this respect. When regener- 
ation of a piece takes place at all, it almost always happens 
that a single more or less perfect animal of typical form results. 
RESULTS. 
In this paper I shall speak only of results obtained on the 
smallest parts capable of regeneration, leaving other questions 
suggested by the experiments for future consideration. From 
numerous experiments, involving many hundreds of S. poly- 
morphus, it was found that the smallest parts capable of 
