McAllister—Cytology and Embryology. 
611 
of a conspicuous spindle, as well as after, may be due to tbe 
action of contractile fibers which in the earlier prophases owing 
to their delicacy are broken and shrivelled during fixation. 
R. Hertwig (41), seeking to harmonize his “Kemplasmare- 
lation” with the fact of the increase in the size of the animal 
egg without accompanying nuclear division, has proposed the 
idea that synapsis is an abortive cell division. The longitudi¬ 
nal splitting of the spirem he regards as a tentative biparti¬ 
tion which does not materialize, but from the standpoint of 
the multiplication of the chromatin has the same effect as a 
typical nuclear division. He offers as evidence that in Pal- 
udina and Periplaneta, as determined by his pupils Popoff (77) 
and Wassilieff (105) respectively, the chromatin seems to 
simulate a resting condition following the longitudinal split¬ 
ting. 
Hertwig’s idea, aimed as it is to explain the enormous growth 
of animal eggs without nuclear division, does not apply at all 
to plants. Here the reduction division and ovogenesis may be 
separated by many cell generations, as is the case in the forma¬ 
tion of the enormous egg of the Gymnosperms. 
The second contraction figure or “second synapsis” seems to 
,have been first described by Miss Sargent in 1896 and 1897 in 
Lilium Martagon (83). She describes this stage as “accom¬ 
panied by all the signs of synapsis,” appearing after a period 
of uniformly distributed spirem. Since then it has been re¬ 
ported by a number of investigators for a variety of species and 
has besides been plainly figured by several authors who have 
however failed to recognize or describe it. 
The second contraction stage has been reported in the fol¬ 
lowing plants: Lilium Martagon (Miss Sargent 83), Lilium 
candidum (Parmer and Moore 23, Mottier 65), Lilium Can- 
adense (Allen 2), Lilium tigrinum (Schaffner 85), Lilium spe- 
ciosum (Gregoire 31), Allium Moly (Miyake 55, Mottier 65), 
Hyacinthus orientalis (Hyde 42), Tradescantia virginica 
(Parmer & Shove 24), Podophyllum peltatum (Overton 73, 
Mottier 66), Oenothera rubrinervis (Gates 30), Oenothera 
