422 MITCHEL CARROLL 
the post spireme stages. If the supernumerary is present in 
triplicate, two of the homologues synapse at the first mitosis, 
while the other remains free and segregates independently. 
Although, as a result of the inconstant valence of the super- 
numerary, the numerical organization of the complex varies in the 
above five animals within the gonad, the count, with two doubtful 
exceptions (one a spermatogonial metaphase, the other a first 
spermatocyte telophase), is consistent for the cyst. The chromo- 
some number is probably constant also for the follicle until after 
the first spermatocyte mitosis. 
Two instances of the reductional non-disjunction of the dyads 
of the supernumerary tetrad in the first maturation mitosis were 
observed. A case of either maturational equational non-dis- 
junction or a peculiar type of reductional non-disjunction of the 
chromatids of the extra tetrad was found. The basis for the 
equational non-disjunction of the two monads of a supernumerary 
dyad was seen in one cell, and the basis for the non-disjunction of 
the members of the extra tetrad in another cell. 
The varying combinations of the supernumerary found in indi- 
vidual 950 and 2525 prior to the second spermatocyte generation, 
must be due to equational non-disjunction, and can be derived 
from a single non-disjunction of the two halves of an unpaired 
inherited extra chromosome at a prespermatogonial division. In 
individuals 980 and 2511 it is necessary to assume two succes- 
sive equational non-disjunctions of inherited supernumeraries. 
A single aberrant individual, such as 980 or 2511, produces, 
with respect to the accessory and the supernumeraries, six classes 
of spermatozoa and may occasionally form two additional classes. 
The origin of the unpaired extra chromosome is unknown. If 
it is a duplicate of an entire member of the normal complex, that 
element is euchromosome no. 3, which it resembles in size and 
form. 
An element such as the camnulan supernumerary, which has 
apparently been transmitted in this race for at least six years, 
may obviously have a significant influence on Mendelian ratios. 
This chromosome too, may furnish a mechanism for the produc- 
tion of mosaics. 
