Miscellaneous. 
173 
nothing but the internal epithelial lamella of the rudiment of the 
polypide ; at the same time the piriform organ is seen to grow and 
envelop this first part so as to form the external muscular lamella 
of the same rudiment. Thus we are gradually led to the state of a 
cell containing a fatty mass and a rudiment of a polypide ; the rest 
of the development is already known. 
B. Vesicul arize ( Serialaria lendigera). —The notched and rounded 
plates are seen to bury themselves in the interior and cause fixa¬ 
tion ; at the same time the two intermediate lobes , as well as all 
the inferior (oral) margin of the crown, close up again above. 
Thus is produced a first cavity in the form of a double T, wider at 
the two extremities, which correspond to the sinking of the above- 
mentioned plates, narrower in the middle, at the level of the two 
lobes which form two thick projections above them. 
Soon after we see the superior (aboral) half of the crown turn so 
as to surround these two projecting lobes ; this turning is not pro¬ 
duced by sudden rotation as in the Escharinae, but by devagination 
like the finger of a glove. Finally there is thus formed a second 
semicircular cavity, which surrounds the two projecting lobes and 
is bounded by the superior (aboral) portion of the crown. The 
aboral surface is, of course, implicated in this movement, and after 
its closure it forms all the external skin. 
At this period the embryo has the form of a rounded sac (the 
future cell), with an outer skin entirely composed of the aboral 
surface. Within and in the lower part of this sac there is a com¬ 
pact mass destined to fall into degenerescence, and composed of the 
long cells of the crown folded three times upon themselves and 
circumscribing two concentric cavities ; this mass fills almost the 
whole interior; towards the top, however, there exists a cavity 
which corresponds to the general cavity of the larva, and in which 
we ought, theoretically, to recognize the notched and rounded plates 
with the organs which pertain to them. I have not yet succeeded 
in recognizing certain traces of the former; but I have often ob¬ 
served in this stage a peculiar mass which may originate from the 
internal sac. 
The rudiment of the polypide seems to me to be formed dif¬ 
ferently from what we have seen in the Escharinae : there is no 
invagination of the outer skin ; and the internal sac may perhaps act 
a part in its formation. 
C. Cellularinze ( Scrupocellaria scruposa). —Here wo again meet 
with the same fundamental processes of turning of the crown and 
formation of the wall of the cell at the expense of the skin of the 
aboral surface. Attachment takes place by means of a sort of chi- 
tinous cupule, which is seen to issue through the aperture leading 
into the cavity of the turned crown, and which, no doubt, is derived 
from the secretion of one of the organs of the oral surface. 
3. Conclusions. —(1) The development of the Chilostomata is, on 
the whole, meroblastic ; the exoderm gives origin to all the organs, 
and plays the part of a true blastoderm ; true inner lamellae have 
only an ephemeral part, and act merely as nutritive vitellus. 
