SOMATIC CHROMOSOMES IN TRADESCANTIA 
The view that such granules do have some special significance is strongly 
favored by Wenrich's (1916) striking observations on Phrynotettix. Not 
only do the granules or chromomeres of a given member of the chromosome 
group in this form have relatively constant sizes and positions, but they 
also show close correspondence in the two members of a conjugating homolo- 
gous pair. This is precisely the type of chromosome organization called 
for by our most promising theory of the cytological mechanism of heredity, 
which it is hoped will find further verification in additional observations 
as carefully made as those of Wenrich. 
Bearing on problem of chromosome reduction. As stated in the intro- 
duction, the theory of telophasic splitting has been incorporated in an 
interpretation placed upon the reduction phenomena by Fraser (1914), 
Digby (1914, 1919), Nothnagel (1916), and certain other writers. The 
split seen in the early heterotypic prophase is said to have its origin in the 
telophase of the last premeiotic division, each chromosome persisting 
through the intervening resting stage in the double condition. It is con- 
sequently held, as fully stated by Digby (1919) in her account of the arche- 
sporial and meiotic phases in Osmunda, that the lateral pairing of slender 
threads in the heterotypic prophase, which a large school of cytologists has 
regarded as a conjugation of entire chromosomes, is in reality only the 
reassociation of the two halves of one chromosome which has been split in 
the preceding telophase. Such a reassociation is thought to occur in every 
prophase, somatic and meiotic, since these workers regard chromosome 
splitting as universally a telophasic phenomenon. The split thus thought 
to form in the premeiotic telophase functions in the homoeotypic mitosis; 
the latter mitosis is therefore looked upon as a continuation of the pre- 
meiotic division, the heterotypic mitosis being an interpolated process 
bringing about reduction. Not only does this premeiotic split reappear 
in the anaphase of the heterotypic mitosis to function in the homoeotypic, 
but a new split developing in the heterotypic telophase, after being tem- 
porarily obscured, functions in the post-homoeotypic division. 
As the writer (1920) has pointed out in a review of Digby's contribution, 
the above outlined theory of reduction has certain advantages, for "it 
allows one interpretation to be placed upon the double spirem in both 
somatic and heteroptyic prophases, . . . and it also helps to explain the 
sudden appearance of the split for the second maturation mitosis in the 
anaphase of the first." 
But can it be said that the chromosomes undergo splitting in the last 
premeiotic telophase and remain double through the ensuing resting stage? 
The writer believes that it has been shown in the case of ordinary somatic 
mitosis in Vicia and Tradescantia that the telophasic alveolation is in no 
sense a split. This conclusion rests upon the facts brought out in a detailed 
analysis of the telophasic changes themselves, and upon the fact that the 
early prophasic reticulate condition, which all grant is continuous with 
