547 
in Pinus and Thuja 
through a rearrangement of the substance of which the chromosomes are 
formed, and regards this as proof of the variable nature of these bodies. 
The same writer concludes that the ‘ number and form of the chromosomes 
typical of any species is evidence rather of the organizing function of 
the cell as a whole than of the independent nature of the chromosomes 
themselves 
In connexion with this theory of the individuality of the chromomeres 
and variability of the chromosomes another set of phenomena must be taken 
into consideration, namely, the origin of the chromosomes from the male 
and female ancestry respectively, and the possibility of their recognition 
in the resting nucleus. As implied above it has been quite generally 
accepted that the two sets of chromosomes remain distinct throughout the 
growth period in the life of the organism and unite only at the time of 
meiosis. This supposition has been attacked by Mottier (’07) and also 
by Foot and Strobell (’07). Mottier (’07) sees no reason for regarding the 
chromatin as remaining in such a complete state of segregation, since there 
is but one known genus [Pinus) in which the maternal and paternal chromo- 
somes do not entirely lose their identity at the time of fecundation. He 
also points out the fact that any interchange or pairing of pangens may 
as readily take place at this time as during meiosis. There is no time it 
seems in the entire process which is so well fitted for distribution and 
rearrangement as the stage during which the chromatin exists in the finely 
divided state connected by delicate anastomosing linin threads. 
Foot and Strobell (’07) have shown for Anasa tristis that the morpho- 
logical identity of the chromosomes is entirely lost during the rest period 
of the first spermatocyte, but that among the eleven chromosomes which 
emerge from this resting nucleus there are three which differ so markedly 
from the others that they are readily distinguished from the early prophase 
to the telophase of the second spindle. These forms are the so-called 
eccentric chromosome, the microchromosome, and a large cross-shaped 
one. These authors conclude, however, that this is not an indication of 
the morphological continuity of these forms, for it is argued that if during 
the growth period the chromosomes pass over into the form of a chromatin 
reticulum, skein, or granules, there is no ground for asserting that the 
chromosomes have retained intact their morphological continuity. It is 
also maintained that no basis exists in fact for asserting that the paired 
bivalents are two of the somatics of the maternal and paternal ancestry 
which have remained together. It is urged that the chromosomes which 
make up the heterotype bivalents are formed anew out of the material 
of the chromosomes of the preceding generation, a view which harmonizes 
with that set forth by Mottier (’07) and by Farmer (’07). 
It is a fact worthy of note that Foot and Strobell have based their 
conclusions on the same data from which Montgomery, Stevens, Wilson, 
P p 1 
