ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
189 
INVERTEBRATA. 
Potamoplankton.* * * § — Dr. O. Zacharias discusses the plankton which 
he has demonstrated in many rivers. It consists of Protozoa, Rotifers, 
and Crustacea (lists of which are given), accompanied by many minute 
plants, — Phycochromacese, Chlorophycem, and Diatoms. 
Earthworms and Moles. f — Prof. J. Ritzema Bos corroborates very 
circumstantially the often asserted, but often doubted, fact that moles 
store earthworms for winter and wound them so that they are unable 
to escape. About 300 were got from one mole’s nest, all decapitated. 
Three to five segments had been bitten off. This prevents burrowing, 
and the cold weather probably prevents rapid regeneration. 
Mollusca. 
Abyssal Molluscs.J — M. Arnould Locard points out that, besides 
the various littoral areas peopled by Molluscs, there is in the Atlantic, 
as in the Mediterranean, an abyssal area, inhabited by a “ polybathic ” 
Molluscan fauna, the members of which are able to live and develop at 
depths of 2000 m. or more. This fauna is rich in Gastropods, and also 
includes Scaphopods and many Lamellibranchs. 
a. Cephalopoda. 
Posterior Salivary Glands of Octopoda.§ — Dr. R. Krause has inves- 
tigated the structure and function of the posterior salivary glands of the 
Octopoda. He concludes, contrary to the opinion of most investigators, 
that these glands have a considerable functional significance. The name 
‘•'pharyngeal mucous glands,” proposed by Krukenberg, and accepted, 
among others, by Vogt and Jung, he regards as quite unsuitable, for 
these glands do not secrete mucus, at least not in appreciable quantities. 
On the other hand, their secretion is rich in albuminates, and has a 
powerful fibrinolytic effect. To many animals the secretion is a deadly 
poison, probably operating on the central nervous organs, and it is used 
by Octopus for killing the animals required for food. The glands show 
a singular kind of secreting mechanism, which is conditioned by the 
peculiarities of their blood-supply. 
y. Gastropoda. 
Nerve-Cells of Gastropods. || — Mr. C. F. W. McClure finds that the 
nerve-cells of Helix , Avion, and Limax contain a large number of small 
bodies, which appear granular in character and are arranged in rows. 
Their staining affinities make it probable that they are essentially 
homologous with the chromophilous substance found in the nerve-cells 
of Vertebrates. 
Fibrils were found in the axis-cylinder processes and cell-bodies of 
these nerve-cells. Their arrangement in the cell-body showed con- 
siderable diversity. In the majority, a concentric arrangement of fibrils 
* Zool. Anzeig., xxi. (1898) pp. 41-8. 
t Biol. Centralbl., xviii. (1898) pp. 63-4. 
X Comptes Rendus, cxxvi. (1898) pp. 275-7. 
§ SB. K. Preuss. Akad. Wiss. Berlin, 1897, pp. 1085-98. 
|| Zool. Jahrb., xi. (1897) pp. 13-60 (2 pis ). 
