410 - MITCHEL CARROLL 
‘The same phenomenon was frequently found in the testis also 
and in some first spermatocyte mitoses, the isolated portion when 
present, behaving in every way like an independent chromosome 
exceptionally dividing in the equator of the spindle or passing 
undivided to one pole.”’ 
The above quotation suggests that there was some numerical 
variation, due to fragmentation or the presence or absence of 
supernumeraries within individuals of the species of Hemip- 
tera referred to. But one is unable to form an opinion in re- 
gard to the real nature or extent of this variation from a perusal 
of the paper from which the above quotation is taken, or from a 
previous account of the same species by those authors (Foot and 
Strobell, 09). Nor do their photographs as published make the 
matter any clearer. 
Payne (714) reviews the work of earlier investigators (whose 
results were not in agreement) on Forficula auricularia and 
reports that the apparent numerical variations found in indi- 
viduals of this species are due to the failure of certain spermato- 
gonial chromosomes to pair at times during synapsis. He found 
that the elements which fail to conjugate may or may not divide’ 
in the first division. He was unable to determine if they divide 
in but one of the two maturation divisions as is ‘typical for super- 
numeraries. In one individual variations were found in the 
spermatogonial complexes, but these were explained as possibly 
due to pathological conditions. 
So with the exception of a few cells observed by Wilson (’09 b) 
and Payne (’14), there is no record of clear-cut numerical varia- 
tions in the chromosome group within the germ cells of the indi- 
vidual, and even the above two exceptions to the rule of 
constancy in the chromosome count for the individual are not 
comparable to the wide variations just described for Camnula. 
B. Nature of supernumeraries 
If we accept the theory of the individuality, or the genetic 
continuity, of the chromosomes, it follows that unpaired extra ele- 
ments are duplicates of chromosomes or parts of chromosomes of 
