26 
Dr. Carpenter, on the Development of 
of them with a peduncular elongation still projecting from 
its mouth, as seen at fig. 13, a (an appearance which is not at 
all unfrequent, and which is often due, I believe, to the de- 
tachment of the embryo bj the rupture of its peduncle, in the 
very act of opening the capsule) ; it happened that another 
and somewhat larger embryo was swimming near, and the 
currents produced by the ciliary action of both drew their 
anterior extremities together, in such a manner that the 
peduncle of vitellus protruding from the mouth of the one 
inserted itself into the mouth of the other, and the two re- 
mained for some time in this close relation, notwithstanding 
that I purposely agitated the water in the trough that con- 
tained them, in a manner that would have caused the separa- 
tion of bodies in mere juxtaposition. It seemed that the 
ciliary action of the larger embryo was more powerful than 
that of the other ; for I could distinctly perceive, through its 
transparent neck, the detachment of particles belonging to the 
projecting peduncle of the other, and their passage down its 
own oesophagus ; and whilst the size of the larger did not 
much exceed that of the smaller when they first came into 
mutual proximity, the former, in the course of a couple of 
hours, had appropriated so much of what belonged to the 
latter, that their comparative dimensions became more nearly 
as three to two. 
Though 1 have spoken of distention of the gastric cavity by 
the new vitellus thus strangely introduced, I do not mean to 
affirm that its enlargement is solely due to such distention 
from within. On the contrary, I have met with obvious evi- 
dence that the cavity enlarges to receive it, by the growth of 
its own walls ; for it sometimes happens that this enlargement 
takes place faster than the new vitellus is introduced, so that a 
void space is left. Generally speaking, however, there is an 
actual distention of the walls of the gastric cavity of the 
embr)o, and this may proceed to such a degree as to involve 
the ciliated lobes also ; and thus all traces of the original 
form may be lost, and nothing apparently remain but an 
ovoidal body, covered with a ciliated membrane, and attached 
by a peduncle to the conglomerate mass (fig. 13, c). If this 
form only was seen by MM. Koren and Danielssen, I am not 
surprised that they should have imagined it to be a pedun- 
cular segment of the vitelline mass. But having traced the 
embryo through every stage, from its first appearance as an 
embryo, to that which it here presents, I feel perfectly satis- 
fied that the bodies in question are genuine embryos, in the 
act of appropriating the supplemental yolk ; and that their 
variety of size merely results from the difference in the amounts 
