980 M. M. Mercaur 
spheres are composed of nutritive chromatin essentially similar to 
that seen in the numerous small chromatin spherules throughout 
the year. 
LOwentTHAL (1904) describes the presence and manner of for- 
mation of one or more large dense chromatin spheres in the nuclei 
of encysting O. ranarum (Text Fig. X). He did not observe their 
extrusion into the cytoplasm. He interprets them as homologous 
with micronuclei, whereas they are probably more comparable with 
a 4 » a ae oe 
Se » 4 Ait? > 
- UN ¢ , | EE Ax 
BAAS 1) Gedo (Ga | 
aa e aya’ “ae” ll 
a b c a. e 
= 9 Boer » 
* @ & F 
Ki g h J ke 
Text Fig. X. Lorwentuav’s figures of the formation of a “micronucleus-like body” 
in the nuclei of O. ranarum: a, a nucleus with chromatin net and nodal thi- 
ckenings; b, a nucleus with the chromatin gathered mostly into large masses at 
the periphery; c. shows the chromatin masses again fragmented; d and e, show 
the gathering of the chromatin at the center of the nucleus; f—h, show the 
separation of a compact darkly-staining chromatin sphere from the central mass, 
and its wandering to the periphery and suggest jits possible extrusion from the 
nucleus: the material remaining in the central mass fragments and scatters 
through the nucleus; j, shows two chromatin masses at the periphery of the 
nucleus; k, a nucleus figured but not described by LozwentHat. X 2250 diameters. 
macronuclei, being probably composed of nutritive chromatin. I have 
not studied the process of formation of these chromatin spheres with 
sufficient care to justify me in commenting upon LOwernrHat’s de- 
scription of the manner of their formation. I would only suggest 
that it must be difficult to be certain of the sequence, of the iso- 
lated phenomena observed. 
NERESHEIMER (1906 and 1907) gives an account of these chro- 
matin spheres essentially similar to that I have given above. He 
emphasises the comparison of the two spheres with the two polar- 
bodies of Metazoa (cf. p. 302). 
