580 
DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 
than the corresponding cavity in figs. 193. 194. 196. The germinal 
vesicle (c) was still present, distended to the diameter of (par. 351.), 
and nearly filled by the twin cells, or germ (bs). 100 diam. 
Fig. 199. An ovum of eleven hours, found half-way between the infundibulum and 
the middle of the Fallopian tube, and measuring in diameter It 
was taken from the same Rabbit as the ova figs. 194 and 195. The 
membrane which in those ova circumscribed the most central portion, 
had disappeared in the ovum of the present figure, leaving the large 
twin cells (bs), surrounded by very minute dark cells (par. 351.). (There 
was a trace of investing membrane (c?) on the right side.) External 
to those minute cells were larger ones, apparently undergoing lique- 
faction. These were surrounded by a proper membrane (e), which had 
become very thin, and seemed about to disappear. Between this mem- 
brane and the membrane f, there was a space filled with transparent 
fluid. The nucleus in each of the large twin cells consisted of two 
parts, — an inner and an outer (pars. 360. 380.). In the centre there 
was a pellucid space (par. 348.). 100 diam. 
Fig. 200. An ovum of thirteen hours found in the Fallopian tube at its middle part, 
and measuring in diameter ys'" +. This ovum was taken from the 
same Rabbit as that in fig 193, from which it differed in the large twin 
cells (bs ) — constituting the germ — having increased in size, and become 
filled with cells, or the foundations of cells, arranged in concentric 
layers (pars. 348.380.). External to these large twin cells were minute 
dark cells ; and these were surrounded by larger ones, undergoing 
liquefaction. The whole were invested by a membrane, between 
which and the membrane f there was a space filled with transparent 
fluid, and containing minute cells which had escaped liquefaction 
(par. 350.). These minute cells presented cells in their interior. (Cells 
were collecting around the membrane f, to form the chorion. These 
have not been represented in the figure). 100 diam. 
Fig. 201. An ovarian ovum of (no more than) 5^ hours, and measuring in diameter 
about ys"'. The Graafian vesicle containing it was vascular, but not 
very large. This ovum was taken from the same Rabbit as the ova of 
figs. 169 and 198. Along with the large twin cells (bs), constituting 
the germ, were other cells of considerable size, destined probably to 
undergo liquefaction ; the whole being surrounded by a proper mem- 
brane which was so large as to be in contact in the greatest part of 
its extent with the membrane f. 100 diam. (par. 360.) 
Fig. 202. An ovum of (no less than) fifty-two hours, which had proceeded so far 
as into the uterus , though the large twin cells (bs), constituting the germ, 
were but little more advanced than those in the ovum fig. 195, of only 
