582 
DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 
(par. 352.). There was present however a minute solitary cell, which 
had escaped liquefaction (par. 350.). 50 diam. 
Fig. 207. An ovum of 24^ hours, found in the Fallopian tube, between its middle 
part and the uterus. It measured in diameter tt". The twin cells ( bs ) 
which occupied its centre (par. 352.) were of unequal size, and filled 
with cells. Several of the latter, situated in the centre of each twin 
cell, were larger than the rest ; but it was not easy to distinguish the 
two destined to survive the parent cell (see fig. 209.). The incipient 
chorion ( cho .) had begun to imbibe fluid (f l ), and to rise from the 
membrane f. It presented indistinctly such of the cells, entering into 
its formation, as had not fully coalesced. Some of these have been re- 
presented in the figure. This ovum was taken from the same Rabbit 
as that in fig. 204. 100 diam. 
Fig. 208. An ovum of 23^ hours, found in the Fallopian tube, on the ovarian side 
of its middle part, and measuring in diameter -jV". This ovum was 
taken from the same Rabbit as the ova in figs. 206 and 209. It was 
not figured until between seven and eight weeks after death, having been 
preserved in the manner recommended in the “ Second Series” of these 
Researches par. 313. The twin cells (bs) corresponding to those in the 
preceding figure (par. 352.) were, like them, of unequal size (pars. 355. 
356.) but considerably smaller. Their interior presented other cells, 
each of which had its nucleus. In the centre of the latter was a pel- 
lucid space. (On the membrane f were cells, collected to give origin to 
the chorion (par. 372.). These have not been represented in the figure.) 
100 diam. 
Fig. 209. An ovum of 23^ hours from the ovarian side of the middle of the Fallo- 
pian tube, and measuring in diameter It was taken from the 
same Rabbit as the ova in figs. 206 and 208. Twin cells, such as those 
in most of the figures from fig. 187 to fig. 208 inclusive, were now no 
longer seen (par. 352.), the number of cells present being four (bs). 
Thus two — and only two — of the cells with which each twin cell becomes 
filled, had survived their parent (twin) cell, — all the rest, as well as 
the membrane of the parent cell, having disappeared by liquefaction. 
(Two or three cells however of extreme minuteness had not yet disap- 
peared (par. 350.). One of these is represented in the figure.) The 
four cells were not elliptical, as in the early state (see the correspond- 
ing objects with the twin cells of fig. 207-), but globular in form 
(par. 355.). Two of them were larger than the other two ; a difference 
perhaps referable to an inequality in the size of the parent cells (see 
figs. 207 and 208.) (par. 356.). The interior of the four cells resembled 
that of the two in fig. 206, except that in one the central pellucid space 
