540 
DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 
Plate XXVII. fig. 230, may not equal the number arising in the germinal vesicle or 
original parent cell. 
354. Very interesting states of the germ are met with, representing the transition 
between what in my last memoir, for a temporary purpose, were denominated C£ stages.” 
Two or three of these will be found among the figures, and may serve as specimens 
of these transition states. Thus in the ovum Plate XXVI. fig. 211, there were pre- 
sent five cells, namely, three large ones, the membranes of each of which seemed about 
to liquefy and give birth to a progeny of two ; and two small ones just brought forth 
by their now vanished parent cell, which (before its disappearance) had made the 
fourth of the large cells in the figure. Again, in the germ fig. 215. the number of 
cells was more than eight, but less than sixteen. Here most of the cells were of equal 
size; but among them were cells considerably smaller, so that the state seemed com- 
parable to that in fig. 211, though differing from it in the size and number of the 
cells. 
355. The cells are at first elliptical, like the discs of which they are an altered 
state. Their form is subsequently globular. In the first set (Plate XXVI. figs. 206. 
207- hs), the dimensions of the containing cavity scarcely admit of this change in 
form. But there is sometimes observed a tendency to undergo it (fig. 208.), and 
flattening occurs where the two cells are in contact with one another (fig. 20/- and 
“ Second Series,” l. c., Plate VIII. fig. 143.)'f~. That such an alteration in the form 
(from elliptical to globular) takes place, we obtain an interesting proof on comparing 
figs. 207. 211 and 212. The cells contained in the twin cells of fig. 207. were ellip- 
tical; corresponding cells in fig. 211. had become globular. The two small cells of 
this figure, which had been liberated, were less elliptical than those still within the 
parent cells. The outer cells in the germ (bs) of fig. 212. corresponded to the elliptic- 
cells in fig. 211, but had undergone the usual change in form. The inner cells of 
the germ ( bs ) in fig. 222. were still elliptical; those in fig. 208. had become nearly 
globular. And in all later stages of the germ where cells have reached their matu- 
rity, the same change in form is found to have taken place (Plate XXVI. fig. 220. 
Plate XXVII. figs. 223. 224.) 
356. A difference in size frequent in the first set of young cells (Plate XXVI. figs. 
207. 208.), appears to be the cause of unequal size sometimes observed in the succeed- 
ing set (fig. 209.). 
f Having in my “Second Series” (/. c., par. 306.) expressed a doubt whether the two objects contained 
within the ovum in Plate VIII. fig. 143. of that memoir were two yelk-balls, I have now to state my convic- 
tion that such was not the case ; but that the figure in question exhibits a condition of the germ approaching 
(but earlier than) that in the present paper, Plate XXVI. fig. ‘207, the interior of its two cells not having been 
distinctly seen, with the magnifying power then employed. 
+ The transitory cells which liquefy as the two essential cells advance (par. 349.) do not perhaps, in general, 
attain the globular form. They often resemble mere discs, the surface of which is membranous, and the 
most superficial part of the interior of which has passed into fluid. Where, however, such transitory cells 
escape liquefaction for a while (par. 350.), they become globular. 
