A Comparative Study of the Clu-oniosomes etc. 
287 
smaller autosome gemini aud a pair of allosomes {xy). In E. curvata 
there are nine bivalent chroniosomes and one univalent chromosonie (ä); 
here, also, there are present a macrochromosome geminus and eight 
smaller autosome gemini, The univalent ai-chromosome retains its Con- 
nections with the autosomes. 
9. The first spermatocyte division is transverse and reductionaL 
In E. hinotata aU the chromosomes separate simultaneoulsy ; in E. curvata 
the avchromosome lags, and is lengthened in the direction of the spindle. 
This lagging is probably due to the thick fibers connecting the rr-chromo- 
some to the two groups of separating autosomes. The x-chromosome 
usuaUy passes undivided to one of the two second spermatocytes, but 
exceptionaUy it is pulled in two. 
10. The second spermatocyte division is longitudinal and equational. 
In both species all the chromosomes separate siniultaneously. All the 
spermatids of E. Unotata contain ten chromosomes, one chromosome 
{x or y) retains its stainabihty longer than the other nine. In E. curvata 
half the spermatids contain ten chromosomes, and the other half nine. 
In those with ten chromosomes one (x) chromosome retains its deep 
stainability. 
Cambridge, Mass., April 15, 1912. 
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