614 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Development of Salpa fusiformis.* — Dr. K. Heider gives tlie fol- 
lowing summary of liis results. The segmentation is total and unequal 
(Todaro, Salensky). There is no segmentation-cavity (Salensky). 
During the cleavage, follicle-cells or kalymmocytes migrate into the 
embryo-sac, surround the embryo, and insinuate themselves between 
the blastomeres, by which they are finally assimilated (Todaro, &c.). 
It does not seem to have been satisfactorily proved that they have a 
formative as well as a nutritive role. 
At an early stage the embryo shows large and small cells. The 
large blastomeres represent the meso-endoderm ; the small cells are in 
part kalymmocytes, in part ectodermic. The epithelial elevation and 
the embryo-sac take no share in forming the embryo (Barrois and 
Todaro), but give origin to the primary placenta and the Faltenhulle. 
A provisional ectodermic or amnion-fold connects the embryo with the 
placenta; its cavity is subsequently filled up by proliferation, and 
the ectodermic basal plate is formed at this spot. 
The cloacal cavity arises early as an unpaired ectoderm-invagination 
from the lower basal surface of the embryo ; the opening of this invagi- 
nation is soon closed ; the cells near the opening form a plug, around 
which the rudiment of the pharynx arises ; the plug persists as an endo- 
pharyngeal cell-strand. 
The pharyngeal cavity developes independently of the cloacal cavity 
(Todaro, Brooks). It is formed by certain w blastomeres ” which arrange 
themselves in the vicinity of the above-mentioned cell-plug, and produce 
the endodermic epithelium. The gill, first represented by Kiemenwulste , 
arises from the septum between the pharyngeal and cloacal cavities 
(Brooks), by the formation of the two gill-clefts. 
Those blastomeres which are not used in forming the endodcrm 
produce by continued division a mesenchyme which fills the primary 
body-cavity of the embryo. This mesenchyme forms inter alia the paired 
muscle-plates. The cloacal cavity sends forwards a narrow diverticulum 
lying under the rudiment of the central nervous system. This diver- 
ticulum seems to open at the spot where the neural canal communicates 
with the pharynx (the rudiment of the ciliated groove). In later stages 
a secondary portion of the placenta is formed by a development of the 
parietal layer ( Mauerblait ). The supra-placentar cavity is filled up by 
a tissue formed by proliferation from the upper wall of the placenta and 
from the blood-forming bud. 
Slollusca. 
a. Cephalopoda. 
Cephalopods of the Gulf of Naples.f — Sig. G-. Jatta gives a system- 
atic account of the ^ Cephalopods found in the Gulf of Naples. It is 
prefaced by a short essay on the general habits of these animals ; by some 
account of the head, arms, funnel, and mantle ; by a short history of 
different classifications ; and by a series of very useful comparative 
tables contrasting orders, sub-orders, families, and genera. The classi- 
* Abh. Senckenberg. Gesellsch., xviii. (1895), received Oet. 1896, pp. 367-455 
(6 pis., figs. A-S). 
t ‘Fauna und Flora des Golfes von Neapel,’ 23. Monographie, Berlin, 4to, xi. 
and 264 pp., 64 figs, and atlas (not to hand) of 31 pis. 
