8 BOTANICAL GAZETTE [JANUARY 
behavior of the polar nuclei, serve, he believes, better to refute 
than to support Porscu’s theory. 
Other valid criticisms might be offered, but we need not do 
this here, since, even if we were to accept the theory, the. question 
as to the most primitive type of angiospermous embryo sac would 
still remain unsolved. 
In a recent publication (9) ae after considering the course 
of development of the ordinary angiospermous embryo sac, as well 
as of such peculiar types as occur in Gunnera macrophylla, Peperomia 
pellucida, P. hispidula, and the Pennaeaceae, arrives at conclu- 
sions quite different from those published slightly earlier by 
CoutteR (5). According to CouLTER, the most important of the 
five nuclear divisions in the development of the ordinary embryo 
sac are the first two, which result in the formation of tetrads. 
CouLtTeER asserts that, so far as we know, if fertilization is to occur 
later, the reduction divisions are not omitted; and that whether 
the number of divisions of the embryo sac mother cell is reduced 
from 5 to 4, or even to 3, the reduction divisions are never omitted. 
In such forms as Peperomia, in spite of the fact that the embryo 
sac contains 16 nuclei, there are only 4 divisions of the embryo 
sac mother cell, instead of 5 as in the ordinary 8-nucleate type 
of embryo sac. 
To this view Ernst replies: ‘Die Entwicklungsvorginge im 
Embryosack scheinen mir unabhingig von seiner Entstehung 
betrachtet werden zu miissen.” So Ernst holds that although 
the omission of tetrad formation is a reduction of the course of 
development and not a primitive character, it has, nevertheless, 
no influence on the development of the embryo sac, and that the 
5 divisions of the embryo sac mother cell resulting in the 8-nucleate 
sac belong to two entirely different phases of development; that 
is, formation of spores, characterized by reduction of chromosomes, 
and germination of spores, characterized by polarity, number of 
nuclear divisions, position of nuclei, Gertie of vacuoles, and 
cell formation. 
It is evident that CouLtTeR regards the 16-nucleate embryo 
sac of such forms as Peperomia as derived by a reduction of the 
divisions of the embryo sac mother cell to 4 instead of 5. ERnst, 
