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Chromosomes in the Spermatogenesis of Anasa Tristis 
present, and we must, therefore, interpret this body either as the chro- 
mosome-nucleolus of Wilson and Montgomery, or as a true plasmosome. 
As the presence of a plasmosome in the nucleus at these stages is the 
typical phenomenon familiar in all known forms (its absence being most 
exceptional) we feel justified in interpreting the structure we find in 
the resting nucleus as a true plasmosome and not an odd _ persisting 
spermatogonial chromosome, 1. e., chromosome nucleolus. 
Text Fic. 2. Reproductions of three of Wilson’s sketches of Anasa tristis, 
05. @, Contraction-phase of synaptic period, showing ‘“ accessory” (h) and 
plasmosome (p); k, polar view of metaphase group, first division, 
m, n, anaphases of second division, showing division of m-chromosomes and 
the undivided heterotropic chromosome. 
In our smear preparations we do not find two nucleolar structures of 
equal or nearly equal size such as Montgomery (Fig. 75, Text Fig. 1) 
and Wilson (a, Text Fig. 2) find in their sections at this stage. 
As the chromosomes begin to form we often find, in addition to the 
persisting plasmosome, parts of one or more of the chromosomes or 
entire chromosomes condensed into a nucleolar-like mass, but we cannot 
interpret this as the normal condition. Such an abnormal appearance 
of several of the chromosomes is shown in Photo. 13, Plate I. The per- 
sisting plasmosome is present and parts of at least four of the chromo- 
somes show evidence of this abnormal nucleolar-like condensation. This 
