Pseudo-Eeduction in the Oögenesis of AUolobopliora foetida. 
150 
We believe tliat Photos 13 and 14 represcnt the revers of the 
process shown in Photos 6, 7 and 9, and that the thin threads of Photos 13 
and 14 represent attenuated bivalents and not nnivalents. The bivalent 
cliromosomes of Photos 2, 3, 4 and 5 become metamorphosed into the 
resting nuclens and at the latest stage these bivalents can still be iden- 
tified as chromosomes, they appear as exceedingly attenuated threads. 
We believe therefore, that when threads resembling these reappear after 
the long grov'th period, it is reasonable to interpret them as having the 
saine value as the attenuated threads which become metamorphosed into 
the resting nucleus. Their further development Supports this Interpre- 
tation for reversing the earlier process, they contract and become shorter 
and thicker until we have again a group of pseudo-reduced chromosomes 
as in Photos 2 to 5, with the important addition that in this post growth 
period group the transverse constriction typical of the tetrad is clearly 
seen, as well as the longitudinal split which can be traced back to the 
leptotene stage (Photo 14) and forward to at least the anaphase of the 
first division. 
In Photo 15 the leptotene threads of Photos 13 and 14 are represented 
by shorter, thicker Strands and this condition is even more satisfactorily 
shown in Photos 113, 114 and 115 [Foot and Strobell (05)]. 
In Photos 16 and 17 the Strands have contracted still further and many 
distinct bivalents are easily recognized. One of these just below the small 
nucleolus in photo 16 shows an interesting phase — the end in contact 
with the small nucleolus showing the thin thread of the leptotene stage while 
the other end has reached the stage of contraction showing the typical 
longitudinal split. ln many cases the bivalent chromosomes reach the 
diplotene stage (Photo 18) without showing the usual longitudinal split. 
In Photo 18 four of the bivalents have separated at their transverse point 
of constriction and at least three of them form typical diplotene groups, 
but in the light of all the other preparations it is e\ddent that the line of 
Separation of these two halves has no Connection wdth the longitudinal 
split of the pachytene or leptotene (Photo 14) stages, but the condition 
is due to their precocious transverse Separation. 
The transverse fission and also the longitudinal split are clearly demon- 
strated in Photo 19. We believe the longitudinal split of these chromo- 
somes can be traced back step by step to the earlier stages even to the 
leptotene stage. For further demonstration of this see Foot and Strobell 
(05) plates 7, 8 and 9. The Photos of plate 9 demonstrate also that the 
first maturation dhision separates these chromosomes at their transverse 
point of fission. 
