No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 3890 
figures as an oocyte (Plate XII; Fig. 6), is about like that 
of my Fig. 39. He does not believe that synizesis is a nor- 
mal stage in the development of the odcytes of Rana, although 
he figures contraction stages of the nuclei in cells which he 
considers as o6gonia that are not able to develop into oocytes. 
His description of the nucleus of one of these “degenerating” 
cells is as follows: “On constate que les microsomes constitutifs 
du réticulum chromatique se gonfluent, se soudent les uns aux 
autres, forment des amas irréguliers qui se colorent comme 
les chromosomes des noyaux en mitose. Ces amas peuvent 
rester isolés dans l’aire nucléaire ou s’amalgamer en un bloc 
chromatique de faibles dimensions.”’ The one figure which 
Bouin gives of such nucleus (Plate XI; Fig. 15), shows the 
synizesis stage in Rana which corresponds closely to that in 
Bufo shown in Fig. 25; and many of his other figures show 
post-synizesis stages comparable to those in Bufo (Plate XI; 
Figs. 10, 11: Plate XII; Figs. 2-5). 
In a recent paper Lams (57) has given a description of the 
stages in the early development of the oocytes of Rana tempo- 
raria which were overlooked by Bouin. According to this 
investigator the nuclear membrane does not disappear at any 
time during the transition of the oogonia into the oocytes. In 
the young odcytes the chromatin filaments gradually condense 
at one pole of the nucleus until they form a rounded, deeply 
staining mass which appears much like that shown in my Fig. 
25. In post-synizesis stages this contracted mass resolves into 
a system of filaments which subsequently divide longitudinally 
and scatter throughout the nucleus. This work of Lams, with 
that of Bataillon and Leydig, furnishes conclusive evidence 
that synizesis is a normal stage in the development of the 
oocytes of Rana. 
It is unfortunate that the contracted condition of the nuclear 
contents during synizesis prevents a detailed study of the 
changes taking place in the chromatin at this time. It is 
evident that during synizesis the nuclear reticulum is no longer 
continuous, and that it becomes broken up into a large number 
of exceedingly fine filaments. Some of these filaments appear 
