QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE, 37 
invaginations of the epiblast, he has been anticipated by Lan- 
kester (‘ Proc. Roy. Soc.,’ No. 151, 1874; ‘ Annals of Natural 
History,’ February, 1875; and this Journal, October, 1874). 
Grenacher (Kélliker and Sieb. Zeitschrift, No. 4, 1874) 
also describes the development of an unknown Dibranchiate 
Cephalopod, the eggs of which were found floating during 
his voyage to the Canary Islands. Very important results as 
to the development of the eye and ‘‘ white-body” are given, 
which are in general accordance with those given by Lan- 
kester in another part of this number of the Journal. 
On the First Developmental Phenomena in the Egg of the 
Pond-mussel, by Professor Flemming, of Prague (‘ Archiv fur 
Mikrosk. Anat.,’ vol. x, 3rd_ part), is of great value, since it 
gives a very minute study and figures of the cleavage pro- 
cess in regard to the question of nucleus and germinal 
vesicle. The latter, Flemming shows, is extruded as Rich- 
tungsblischen. He also shows that the nuclei become diffused 
before each act of self-division of a cleavage-segment, and 
that they re-form around centres indicated by radiating lines 
of fine granules, denoting the presence of movements towards 
a central spot. 
Tunicata.—Salpa pinnata.— Professor Todaro has communi- 
cated some observations on the development of this animal to 
the Reale Accademia dei Lincei, Feb. 1st, 1874. He de- 
scribes the segmentation of the egg, and the formation of a 
Baer’s cavity, the cover of which has three layers as in Verte- 
brates. Then a Rusconian cavity forms, whether by invagina- 
tion or with any trace of invagination, is not stated. The 
placenta now commences to take on a large development, 
whilst further, an amnion and amniotic cavity develop them- 
selves. The maternal organism exhibits a true uterus, with 
outer smooth muscular coat, a middle vascular tunic, and an 
inner epithelial lining. 
The Production of Buds in the Ascrdians, by Prof. A. Kowa- 
lewsky (§ Archiv fur Mikr. Anat.’, vol. x, 4th part), with two 
plates. 
Semper (Verh. Phys. Med. Gesselsch. Wurzburg, vu 
Bd.) gives an account, with two plates, of his study of the 
development of the Cellulose tunic of the Ascidians. The 
same subject had been recently treated by Dr. Oscar Hert- 
wig, in the ‘ Jenaische Zeitschrift,’ vol. vii, p. 46. Hertwig 
arrived at the following results: The outer cellulose-impreg- 
nated test of Ascidians is not secreted from the “ testa-cells”’ 
of the egg (the persistent ovarian capsule of yellow cells, 
supposed by Kupffer to originate by free cell-formation from 
the yelk of the egg itself, by Kowelawsky to be cells of the 
