DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 577 
Fig. 189. Part of the same ovum more highly magnified. The minute interme- 
diate cells are here seen to have had essentially the same structure as 
the larger ones. The dark objects in the latter were composed of the 
foundations of cells, which seemed to surround a central space. 300 
diam. (par. 351.) 
Fig. 190. An ovum of seventeen hours from the Fallopian tube near its middle, and 
measuring in diameter It was taken from the same Rabbit as the 
ova in figs. 188 and 191. The incipient chorion ( cho .) was beginning 
to imbibe fluid, and to rise from the membrane / (par. 374.). The cells 
in the central portion of the ovum were invested by a proper membrane, 
e (tw'")- Those immediately within this membrane were pretty large, 
and seemed to be undergoing liquefaction (pars. 338. 339. 342. 343. 
360.). Internal to these were smaller cells (surrounding two large 
ones corresponding to the two which occupied the centre of the ovum 
in fig. 191). 100 diam. 
Fig. 191. An ovum of seventeen hours from the Fallopian tube near its middle, 
and measuring in diameter It was taken from the same Rabbit 
as the ova in figs. 188 and 190. The condition of the interior of the 
ovum appeared to be nearly the same as that of the ovum fig. 190. 
The most central part was occupied by two large elliptic cells ( bs ) of 
equal size (y/' in length), surrounded by minute dark objects (par. 
351.), and containing a colourless transparent fluid and a nucleus (par. 
378.) ; the latter presenting in its centre a brilliantly pellucid space. 
These two large cells were in the same locality as the two in fig. 18/ ; 
namely, that in which the point of fecundation is last seen. They con- 
stitute the essential portion of the ovum, that is, the germ (par. 347.). 
100 diam. 
Fig. 1 92. The nucleus of one of the twin cells represented in the preceding figure. 
It measured in diameter about yy/', and the pellucid space in its centre 
about 4 x 0 "'. The outer portion of this nucleus appeared to consist 
almost entirely of the foundations of new cells. 300 diam. (pars. 34/. 
380.) 
Fig. 193. An ovum of thirteen hours from the middle of the Fallopian tube, 
measuring in diameter The membrane /was surrounded by 
minute cells {cho.), destined to coalesce and thus give origin to the cho- 
rion (par. 372.). Only a few of these have been represented in the 
figure (see also figs. 252 and 253.). The cells in the central portion of 
the ovum were invested by a proper membrane (e), between which and 
the membrane /there was a fluid (pars. 338. 339. 342. 343. 360.), con- 
taining two or three minute cells which had escaped liquefaction (par. 
350.). The cells immediately internal to the membrane e seemed to be 
4 E 
MDCCCXL. 
