ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
409 
New Mite from Beaver.* — Dr. Kramer describes Eaptosoma trun- 
catum g. et sp. n. from the beaver. It has some of the characters of 
Trouessart’s Chirodiscinae, but is quite distinct. The anterior pair of 
feet and the sternal regions of the second pair are remarkably well 
adapted for clambering among the soft fur, uniting the peculiarities of 
Listrophorus, Chirodiscus, Labidocarpus, and Campylochirus. The first 
two pairs of appendages are two-jointed and shovel-like, the posterior 
feet have distinct attaching discs. The male is strongly compressed 
laterally, truncated posteriorly, and hollowed in adaptation to copula- 
tion. 
Marine Acarina.| — Dr. Trouessart describes some Acarina dredged 
from deep water by Prof. Koehler in the Bay of Biscay. The dredging 
shows that Halicaridae live even at a depth of 1410 metres. The 
cuticle is slightly chitinised and without salient sculpturing ; the hairs 
are generally setiform, not spinous ; two species, out of the four which 
are new, seem to be blind, or at least without cornea, while the other 
two have well- developed eyes. It must also be noted, in connection 
with eyes, that some littoral forms are blind. The systematic part of 
the paper has descriptive notes on Halacarus abyssorum sp. n., H. Gaudani 
sp. n., H . gracilipes Trt., E. oculatus Hodge., H. actenos Trt., Agaue 
aculeata sp. n., Coloboceras Koehleri sp. n., and Leptognathus falcatus 
Hodge. 
6. Crustacea. 
Otocysts of Crustacea and Equilibrium.^ — Prof. J. P. Clark has 
made a study of the relation of the otocysts to equilibrium-phenomena 
in Gelasimus pugilator and Peltyonychus ocellcitus. The work of previous 
investigators furnished evidence in support of the hypothesis that the 
otolith in lower and higher animals is an important mechanical factor 
in the maintenance of equilibrium. The author selected, therefore, for 
investigation crabs whose otocysts contain no otolith. A comparison of 
the results of experiments on these two forms with those obtained by 
other observers on other forms of allied Crustacea shows, in the main, 
agreement in the effects the otocysts have upon the maintenance of 
equilibrium. The evidence at hand justifies the view that the co-ordinate 
movements of equilibrium-phenomena depend in part upon different 
impulses, started in certain nerves by the movements of hair-cells, with 
which they are connected. Some movement of the hair-cell is the 
essential factor. If an otolith be present its pressure or strain may 
modify or intensify the movement of the hair-cell, but it is conceivable 
that the movement of the hair-cell may occur in the absence of an otolith. 
The author adopts the suggestion of Yerworn to substitute the terms 
statocyst and statolith for otocyst and otolith. 
Malacostraca of Baffin Bay and Smith Sound.§ — Herr Axel Ohlin 
discusses 78 species of Malacostraca from these localities. Among the 
new species are the following : — Anonyx affinis , Halirages Nilssoni, 
Protomedeia aberrans. 
* Zool. Anzeig., xix. (1896) pp. 134-6 (2 figs.). 
f Bull. Soc. Zool. France, xxi. (1896) pp. 102-5. 
X Journ. Physiol., xix. (1896) pp. 327-43 (5 figs.). 
§ Acta Univ. Lund., xxxi. (1895) pp. xxii. and 70 (1 map and 1 pi.). 
