SOME OBSERVATIONS ON ACINETARIA. So7 
have an absolutely identical appearance to the ‘ Tinctin- 
korper ” of the Acinetaria. 
(5) In a parasitic form, Tachyblaston ephelotensis, 
which I describe in the second part of this paper, I could 
never find any trace of “'Tinctin-korper.” 
It is interesting to note that in this case the nucleus of the 
host was never ingested by the parasite. 
From a consideration of these points it will, I think, 
become evident that, in the great majority of cases, the 
scattered chromatin granules found in Acinetaria can only 
be regarded as the partially digested nucleus of their prey. 
II]. Tur Consucation or ACINETA PAPILLIFERA. 
Without attempting to give a history of our knowledge of 
conjugation in the Acinetaria (which has already been fully 
done by Biitschli in his great work on Protozoa as regards 
the earlier period), it will be necessary to give a short 
account of the work done by later observers of this process, 
and more particularly of Keppen’s work upon Acineta 
papillifera, the intrinsic merits of which have almost 
entirely been overlooked, owing largely, no doubt, to the 
fact that it was written in Russian. Keppen, in his paper 
published in the ‘ Memoires de la Societé des Naturalistes de 
la Nouvelle Russie,’ Odesse, T. 13, 1888, states that he had 
not been able to follow the whole process of conjugation, of 
which he could only find some stages, but that the little he 
had seen had led him to believe that conjugation in this 
group, as in the Infusoria, was connected with a reformation 
of the nucleus, the new macronucleus being formed from the 
division of the micronucleus. He described in some detail 
the breaking down of the macronucleus, and in the later 
stages he saw amongst the degenerating masses of the old 
macronucleus lightly-staining bodies, which he regarded, on 
the analogy of Ciliata, as the division products of the micro- 
nuclei. Keppen figures four stages in conjugation, of which 
