On the Dimegalous Sperm and Chromosomal Variation of 
Euschistus, with Reference to Chromosomal Continuity. 
By 
Thos. H. Montgoniery, jr. 
University of Pennsylvania, Philadelphia. 
With 1 figure in the text, and plates IX and X. 
I. The Dimegaly of the Sperm Cells. 
In my first paper on spermatogenesisi) the discovery of spermato- 
cytes of two constant sizes was described on pp. 35 — 37, and siimma- 
rized on p. 64 as follows: „There arc 6 foUicles in the testicle, two of which 
contain spermatocytes of about double the size of those in the other 
foUicles. In aU foUicles the spermatogonia are of the same size. About 
the Stage of synapsis the spermatocytes of the large generation commence 
to grow in size more rapidly than tliose of the smaU, and their larger size 
is due to greater increase in the amount of the cytoplasm, idiozome sub~ 
stance and nuclear sap: the amount of the chromatin is the same in sper- 
matocytes of both generations. In the ceUs of the large generation the 
processes of the reduction divisions are exactly the same as in the ceUs 
of the small generation except that in the fornier the cells are larger.” 
Ao one has since then restudied this phenomenon, or found a similar case 
in any other animal, for which reason I decided to reexamine this interesting 
instance. 
First, a word is necessary as to the exact species of Hemipteron in- 
vestigated, a matter of some importance now that it is weU known that 
different species of the same genus may have different chromosomal 
1) 1898. The spermatogenesis of Pentatoma up to the Formation of the Sper- 
matid. Zool. Jahrb. 12. 
