ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
75 
New German Hydrachnidae.* — Herr R. Piersig lias a preliminary 
note on some new species. These include two new species of Libertia , 
L. polita and L. rugosa, an Acercus, A. ligulifer , and two new species of 
Hydrachna , H. crcissipalpis and H. maculifera. Some of the species are 
figured. 
Swiss Arachnids and Myriopods.j — MM. Simon and Broelemann 
publish respectively faunal lists of the above, collected at Bex. Among 
the Arachnids were specimens of the male of the rare Ceto unicolor. The 
characters of the male have hitherto been known only from the brief 
notes of Bertkau, and are here described more fully. 
Pigment of Tardigrades.J— Dr. T. Rywoscli discusses the reddish 
pigment in the epithelial cells of Macrobiotus Oberhduseri Doy. and of 
species of Milnesium. In the mature individuals of the former species it 
is arranged in cross bands, which seem to arise from the confluence of 
longitudinal bands. The pigment does not seem to be a lipochrome ; but 
what it is remains undetermined. It is brought by the body-fluids to the 
cells — which are for some time quite colourless — and gradually accumu- 
lates there. 
Crustacea. 
Respiratory Mechanism in Decapods.§ — Mr. W. Garstang describes 
some adaptations of structure subservient to respiration in Decapod 
Crustaceans which burrow in sand, and discusses the utility of specific 
characters in these forms. Thus, the characters which distinguish the 
different species of Calappa are principally the following : — (1) Propor- 
tion of length to breadth of carapace ; (2) extent of postero-lateral 
clypeiform expansions of carapace ; (3) serrations of carapace on the 
antero-lateral margins and on the edges of the clypeiform expansions ; 
and (4) the hairiness of the pterygostomial regions. In regard to these 
Garstang points out : — (1) that the more elongated species are restricted 
to deeper water than the broader species ; (2) that the clypeiform ex- 
pansions are largest in the shallow- water species, and smallest in those 
which inhabit deep water ; (3) that the denticulations of the antero-lateral 
margins have a sieve-like function in British crabs, and may have had 
the same in the ancestors of Calappa , while the clypeiform expansions 
perhaps present protective resemblance to bivalves; and (4) that the 
pterygostomial hairs serve as a sieve for the finer particles of mud. In 
Matuta, water seems to enter the orbits and travel backwards through 
the orbital gutter into the carpet of hairs (which, when the chelipeds are 
flexed, must furnish a most efficient sieve for the finer particles of mud 
and sand), through which it no doubt eventually makes its way to the 
afferent aperture at the base of the chelipeds. Many of the characters 
which distinguish the species of Albunea , both from one another and 
from their allies, are very probably correlated with the function of 
respiration under arenicolous conditions of life. 
Carcinological Studies. || — Dr. A. E. Ortmann continues his studies 
on Decapods, and deals in this systematic paper especially with those in 
* Zool. Anzeig., xx. (1897) pp. 350-4 (8 figs.). 
t Rev. Suisse Zool., v. (1897) pp. 101-5. 
1 Biol. Centralbl., xvii. (1897) pp. 753-5. 
§ Quart. Journ. Micr. Sci., xl. (1897) pp. 211-32 (3 pis.). 
|| Zool. Jahrb. (Abth. Syst.), x. (1897) pp. 258-372 (1 pi.). 
