ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
803 
Argas reflexus as a Human Parasite.* — Dr. G. Brandes records 
the history of observations as to infection of man by the dove-tick, Argas 
reflexus , whose bite seems to be poisonous. Decent cases make the 
occurrence quite certain. Only certain people are susceptible, however, 
especially the hyperaesthetic. 
Distribution of Halacaridse.f — Dr. E. Trouessart points out that 
a closer study of the distribution of Entomostraca and Acarina around 
the coasts has considerable practical as well as scientific interest, since 
these animals form an important part of the food-supply of fishes. 
In studying the distribution of Halacaridae, Trouessart has been led 
to distinguish four areas : — 
(1) The littoral or coralline areas, characterised by Ithombognathus , 
which is restricted to this area, and by the frequency of Halacarus 
spinifer, H. Chevreuxi, Agaue brevipalpus, &c. 
(2) The granite floor, characterised by Acaromantis squilla , Colo- 
boceras longiusculus , and Scaptognathus iridens. 
(3) The Bryozocn-area, characterised, for instance, by Halacarus 
Murrayi. 
(4) The abyssal area, characterised by very distinct forms : — Hala- 
carus abyssorum , H. Caudani , Agaue aculeata , A. tricuspis , Colobocera 
Koehler i. 
e. Crustacea. 
Nervous System of Crab.f — Herr A. Bethe makes a third com- 
munication in regard to the nervous system of Carcinus msenas, the 
common shore-crab. 
Besides the “ primitive fibrils ” which pass from the lateral processes 
or from the axis-process of the nerve-cell into the peripheral fibre, there 
are many others in the neuron. Experiments make it practically certain 
that the primitive fibrils form the conducting elements of the nervous 
system. 
The remarkable conclusion is maintained that almost all the func 
tions which a nervous system has in relation to the muscular system 
may occur in the crab without the nucleus-bearing portion of the neuron, 
and without the fibrillar framework of the ganglion- cells. 
We cannot unfortunately find space to follow the ingenious author 
in his interesting study of the complex reflexes, in the course of which 
he finds evidence for a morphological conclusion, viz. that the stalked 
eyes represent a pair of appendages. The most important conclusion 
is that ganglion-cells are not necessary for the occurrence of reflexes. 
The brain of the crab is shown to be in part “ a reflex inhibiting 
organ,” and the facts lead Bethe to deny it any intelligence (“ jede Art 
von psychischen Qualitiiten abzusprechen ”). He ends, however, very 
pessimistically, saying that his attempt to make things clearer has only 
resulted in disclosing numerous unsuspected difficulties. 
Peripheral Nervous System of Crayfish. § — Herr W. Schreiber con- 
firms previous accounts of the presence of a sub-epithelial plexus of 
* Centralbl. Bakt. u. Par., xxii. (1897) pp. 747-52. 
t Mem. Soc. Nat. Cherbourg, xxx. (1896-7) pp. 91-8 (3 fi°-s.). 
X Arch. Mikr. Anat., li. (1898) pp. 382-452 (2 pis.). 
§ Anat. Anzeig., xiv. (1898) pp. 273-7 (3 figs.). 
1898 
Y 
