440 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Winter Fauna of the Upper Rhine. * — Herr R. Lauterborn has 
studied the pools and water-basins of the Upper Rhine. He gives lists 
of the Protozoa and Rotifers, and notes that some Protozoa and all the 
species of Notholca predominate in winter. Among Flagellata, Bicosoeca 
socicilis sp. n., Sphserceca Volvox g. et sp. n., 3Iesostigma viride g. et sp. n., 
Gymnodinium ienuissimum sp. n., Holophrya nigricans sp. n., Disemato- 
stoma Butschli g. et sp. n., and Bursaridium Schewiakoivii g. et sp. n. are 
briefly described. 
Mollusca. 
Histology of Mid-gut Gland. | — Prof. J. Frenzel discusses the 
minute structure of the mid-gut gland (liver) of no less than 64 
Lamellibranchs and Gastropods. His previous researches (1886) led 
to the conclusion that this variable gland was a pancreas but not a 
hepato-pancreas. The present paper contains histological contributions 
which the author believes to be necessary before any further conclusions 
are risked. One misses, however, amid the long array of individual 
results, any general summary, which a promised continuation will 
probably supply. 
•y. Gastropoda. 
Nerves of Oculiferous Tentacle of Helix pomatia.ij: — Hr. P. Samassa 
has been able to distinguish the following parts ; central processes of 
sensory cells which branch in an arborescent manner ; fibres of unknown 
origin arising from the lower part of the ganglion and having branched 
endings which form a plexus with the sensory branches ; thirdly, there 
are fibres which arise from the tentacular nerve, divide into two branches 
in the upper part of the ganglion, and send their branches into the pro- 
cesses ; in the lower part of the ganglion there are coiled fibres with 
lateral branches ; there are other fibres w r hich send out a branch towards 
the layer of ganglion-cells, which is probably the process of a ganglionic 
cell ; and, lastly, there are ganglion-cells with one or several processes, 
which are generally branched. The tentacular ganglion probably differs 
in structure from the brain only in the want of motor elements ; it is a 
sensitive part of the central nervous system, and the tentacular nerve is 
to be considered as a connective. 
Hydrobia ulvse.§ — Dr. H. Henking describes the structure of this 
Gastropod, and the way in which the eggs are protected within small 
clumps of agglutinated sand. For although no positive proof was 
forthcoming that the egg-clumps were those of Hydrobia, they were 
found on the majority of the shells dredged, as well as on many different 
kinds of animals living in the same locality. The ciliated larvae were 
observed. Of the anatomy, hitherto but imperfectly described, a full 
account is given. 
Circulatory and Renal Organs of Chitons.|| — Dr. L. Plate has been 
so fortunate as to obtain, on the coast of Iquique, some Chitons as much 
* Biol. Centralbl., xiv. (1894) pp. 390-8. 
f Verh. K. Leop.-Carol. Akad. Halle, lx. (1894) pp. 321-408 (4 pis.). 
+ Zool. JB. (Anat. Abth.), vii. (1894) pp. 592-608 (2 pis.). 
§ Ber. Nat. Ges. Freiburg, viii. (1894) pp. 89-110 (1 pi.). 
|| SB. Akad. Wiss. Berlin, 1893, pp. 962-6. 
