A Study of Chromosomes and Chromatin Nucleoli in Euschistus crassus. 59 
YENS ('08). She says, “As in Metapodius the number of supernunieraries 
is constant for the individual.” Pg. 463. 
In Euschistus variolarius the number of independent chromosome 
fraginents is most variable, a fact easily and definitely determined by 
the aid of the large number of photographs we have taken of complete 
groups of chromosomes in a single embryo. 
The same phenomenon was frequently found in the testis also and 
in some first spermatocyte mitoses, the isolated portion when present, 
beha\’ing in every way like an independent chromosome, exceptionaUy 
dividing in the equator of the spindle or passing undivided to one pole. 
These chromomeres seem to have at least two points in common with 
Moxtgomery’s (11) “minute chromosomes”. First, he does not find 
them constantly present, and second when present, they “behave like 
true chromosomes”. In the foUowing details, however, they are not in 
accord. Montgomery finds the “minute chromosomes” in the resting 
spermatogonia as two minute dense bodies of different volume, which 
he interpreted in 1901 as idiochromosomes. Again he has “never seen 
more than a single one in any first maturation spindle”, on the contrary 
we have found from one to three. Further, he has never found his 
“minute chromosomes” divide in the first spindle, but they pass un- 
divided into the second spermatocyte. On the contrary, we sometimes 
find them dividing in the first spindle, though they more frequently 
do not divide. 
Our photographs in which these chromomeres are demonstrated 
were taken in 1908, and later three plates of these photographs were 
prepared for publication, but we were unable to publish them in the 
journal for which they were prepared. 
Euschistus crassus shows, though in a less marked degree, a similar 
constriction of the chromosomes at ' relatively definite areas, and the 
occasional Separation of such portions from the mother chromosome. 
This is clearly shown in two of the chromosomes of photo 47, and 
in one chromosome of photo 48, and in two of the chromosomes of 
photo 49. 
In Euschistus variolarius the chromosomes sometimes show a budding 
off of part of the chromatin from the side of a chromosome, and this 
budded portion behaves in the same way as when a portion is constricted 
off from the end of the chromosome. Again, some of our Euschistus 
variolarius photographs of ovarian groups of chromosomes at anaphase, 
show each half chromosome composed of a row of smaUer units, sug- 
gesting the chromomeres described by different authors. All such pheno- 
