Miscellaneous. 413 
further fissiparous division. This Lxeberkuehma, so constituted, 
with its two places of emission of pseudopodia situated at the 
two opposite extremities, would answer to the morphological type 
which has served to establish the family of the Amphistomina. It 
may be considered therefore one of those intermediate forms which 
connect separated families.— Comptes Rendus, July 24, 1882, p. 191. 
On the Development of the Alcyonaria. 
By MM. A. Kowatewsky and A. F. Marton. 
During the months of May, June, and July we studied at Mar- 
seilles the embryogeny of three Alcyonida, namely two Clavularice 
and Sympodium coralloides. The segmentation, which had not 
previously been completely observed in any Aleyonarian, was seen 
and followed in all its phases in the ova deposited by Clavularia 
crassa. The fecundated ovum remains for some time without 
dividing. At this period the principal histological reagents (Klei- 
nenberg’s liquid, osmic acid, chromic acid, carmine with borax) are 
powerless to show any nucleus in its interior, while subsequently, 
when the segmentation is completed, the nuclei of the cells, not- 
withstanding their extreme minuteness, are easily recognized. 
Sections of the fecundated ovum show simply a finely granular 
peripheral protoplasmic zone and a central mass of fatty nutritive 
vitellus. The segmentation is rapid and of a quite unexpected 
nature. ‘The primitive nucleus must be unable at its first division 
to carry with it the whole mass of the vitellus as nutritive substance. 
The derived nuclei undoubtedly emigrate towards the periphery, as 
is the case in some Crustacea ; and when they are numerous enough, 
they determine a splitting-up of the vitellus, which becomes rapidly 
marked, producing segmentation-balls which penetrate angularly to 
the centre of the ovum. There is consequently no division into 
two. The ovum appears all at once broken up into at least six 
balls. After this division the distinction between a central nutri- 
tive part, and a peripheral evolutive part persists in the segmenta- 
tion-balls themselves. These first balls, the number of which has 
increased, divide transversely, so as to constitute a peripheral layer 
of evolutive cells, and a central mass of cells in which the nutritive 
vitellus predominates. The same characters are still shown when 
the number of cells has considerably increased by the progress of 
the segmentation. The peripheral protoplasmic cells soon become 
regular, and form a very distinct ectodermic lamella, Beneath this 
the nearest layer of deutoplasmic cells arranges itself into a second 
lamella, the endoderm. The remainder of the deutoplasmie cells 
still occupy the centre of the ovum ; but the contours of these ele- 
ments begin to grow indistinct, and we soon see that, under the 
influence of degenerescence, a great number of the nuclei themselves 
are destroyed. The mass of vitellus in reserve decreases pretty 
rapidly ; and empty spaces, gradually becoming larger, appear in the 
centre of the embryo, which acquires an ovoid form. The larva, 
when it issues from the evum with its characteristic aspect, still 
