ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
181 
branchia with an ordinary lung ( Siphonaria , with intra-pul monary 
brancliia, Planorbis corneus with extra-pulmonary branchia) ; by a 
secondary branchia without any lung ( Ancylus ). 
Dr. Pelseneer gives in detail his reasons for believing that the lung 
of the Pulmonata is the homologue of the pallial cavity of the Strepto- 
neura, but states that the branchiae of Planorbis, & c., are not homologous 
with the ctenidia of the Streptoneura or Opisthobranch Tectibranchiata ; 
they are merely examples of homoplastic organs. 
Larval Kidney of Planorbis and Limneeus.* — Dr. K. von Erlanger 
distinguishes in the Y-shaped primitive kidney a short posterior efferent 
portion, a dilated median portion or ampulla, and an anterior longer 
limb. An oval exit aperture lies a little behind the foot, about half-way 
up the embryo. The iarge size of the ampulla is due to a ventral giant 
cell, which probably contains granular excreta. At the anterior end of 
the third or internal portion, there is a cell with a very large nucleus, 
and this forms the “ funnel,” which opens into the primary body-cavity. 
A very long undulating flagellum works in this internal portion. The 
author inclines to regard the efferent part as an ectodermic invagination. 
5. Lamellibrancliiata. 
Phagocytosis in Lamellibranchs.f — Dr. 0. de Bruyne has studied 
the phenomena of phagocytosis — migration of phagocytes, incorporation 
of solid foreign bodies, and excretion — in the gills, palps, mantle, &c., of 
Mytilus edulis , Ostrea edulis , TJnio pictorum , and Anodonta cygnea. 
Observations on the living animals were corroborated by the study 
of sections, and many results of importance have been arrived at. 
Among the more important general conclusions are the following : — 
The epithelium is invaded by leucocytes coming from the subjacent 
tissues. Among them are healthy leucocytes, degenerating leucocytes, 
and phagocytes. 
They occur either isolated or grouped, and they force a way partly 
by separating, partly by eroding the epithelial cells. Neighbouring 
cavities are sometimes separated by delicate partitions or epithelial 
residues, which gradually disappear under the pressure or dissolving 
action of the leucocytes. Thus large intra-epithelial lacunae are formed. 
The communication between these cavities and the deeper tissues is 
often invisible, but sometimes very distinct. 
A sortie of leucocytes, carrying inclusions which result from de- 
generated elements, or from actively functioning organs, or from foreign 
bodies, is a normal phenomenon in Lamellibranchs, which may in certain 
conditions be greatly exaggerated. The sortie is often accompanied by 
lesions in the mucous and integumentary epithelial. Its end is to 
purify the tissues, and the result is excretion. 
Arthropoda. 
a. Insecta. 
Speculative Method in Entomology.^ — Prof. E. Meldola in his 
presidential address to the Entomological Society of London, pleads for 
* Arch. Biol., xiv. (1895) pp. 127-38 (1 pi.), t Tom. cit., pp. 161-241 (3 pis.). 
% Nature, liii. (1896) pp. 352-6. 
o 
1896 
