294 Wisconsin Academy of Sciences, Arts, and Letters. 
General Considerations 
As described above, the telophasic chromosomes of Podophyllum 
become transformed into reticulate bands by progressive internal 
alveolation. These bands are held to represent the individual 
chromosomes, which again condense during the prophases into 
irregularly coiled zigzag threads. These threads thicken and un¬ 
dergo a longitudinal split, which split persists until the daughter 
chromosomes are separated at metaphase. As pointed out, I find 
no evidence from my studies on this plant to support the view 
that the telophasic chromosomes undergo a median vacuolation 
to bring about a longitudinal split as held by von Schustow, 
(’IB), I am also unable to accept the view held by Dehorne (’ll), 
Granier and Boule (’ll), and Lundegard (’12a, c ) that a longi¬ 
tudinal splitting occurs in the chromosomes during the anaphases, 
and cannot agree with Lundegard, who maintains that the ana- 
phasic split is quite as evident and distinct as in the prophases, 
and who holds with Fraser and Snell (Tl) and with Miss Digby 
(’10, 19) that each chromosome appears from the resting reti¬ 
culum already double. I agree with the interpretation of Gre- 
goire and especially with that of Sharp (’13) that the duality of 
the individual chromosomes is the result of the longitudinal 
splitting of the prophasic threads, which are evolved by progres¬ 
sive condensation from the reticulate chromosomes of the resting 
nucleus. My view as to the method of the vacuolation of the 
chromosomes also accords in general with that of Lawson (’03, 
’ll, ’12). 
Sharp (T3) points out that the telophasic alveolation of the 
chromosomes is too irregular to permit of its being regarded as 
a longitudinal splitting. The telophasic figures of Fraser and 
Snell (’ll) and of Lundegard (’12 a, c), have been criticized by 
Sharp as lacking details of alveolation. Lundegard (’15) points 
out that von Schustow’s (T3) results support his views as to the 
duality of the caryotin and further calls attention to the fact that 
Sharp (T3) fails to take into account that Lundegard is the only 
one who has studied the arrangement of the caryotin in the living 
cell and maintains that fixed material does not represent the 
facts. 
The chromosome halves are always superposed at the point of 
insertion, as emphasized by Gregoire (’12), and as stated by Lun- 
