ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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appendages, undergo histolysis, and become the ellipsoid bodies which 
Malaquin has described. 
Free-Swimming Copepods from West Coast of Ireland.* — Mr. I. C. 
Thompson describes the Copepods of some tow-net material from off 
Valencia. Of 22 species, 6 were rare, viz. Meiridia armata , Candace 
pectinaia, Pseudocalanus armatus , Monstrilla rigida, Corycseus speciosus, 
and Oncsea mediterranean The occurrence of the two last, which are 
southern species, may indicate Gulf Stream influence. The collection, 
like another made by Prof. Herdman, illustrates the relatively large 
number of different genera, for the 22 species represent 18 genera. 
Brain and Optic Ganglion of Leptodora hyalina.f — Mr. E. P. Carl- 
ton has made a study of the minute structure of these parts. The brain 
is covered with cortical cells, except at the superficial origin of the 
nerves and over an area located dorsolaterally. The interior is com- 
posed of the medulla, or Punldsubstanz, which is divided by commissures 
and cells into distinct subdivisions, and of three groups of nerve-cells. 
In the optic ganglion, likewise, there is a superficial layer of cortical 
cells and a central medulla. The author describes the various parts in 
detail. 
South African Entomostraca. J — Prof. G. 0. Sars reared 20 species of 
Entomostraca from some dried mud obtained from a swamp at Knysna, 
some distance east of the Cape of Good Hope. Nothing has been 
hitherto published about the freshwater Entomostraca of that remote 
region, hence the special interest of this paper. The mud yielded 
9 Cladocera, 10 Ostracoda, and 1 Copepod, of which 11 species were 
apparently new to science. 
Classification of Trilobites.§ — Mr. C. E. Beecher completes his out- 
line of a natural classification of the Trilobites. 
Order A. Hypoparia ord. n. Free cheeks forming a continuous 
marginal ventral plate of the cephalon, and in some forms also extending 
over the dorsal side at the genal angles. Suture ventral, marginal, or 
sub-marginal. Compound paired eyes absent ; simple eyes may occur 
on each fixed cheek, singly or in pairs. Includes the families Agno- 
stidae, Harpedidae, and Trinucleidae. 
Order B. Opisthoparia ord. n. Free cheeks generally separate,, 
always bearing the genal angles. Facial sutures extending forwards 
from the posterior part of the cephalon within the genal angles, and 
cutting the anterior margin separately, or rarely uniting in front of the 
glabella. Compound paired holochroal eyes on free cheeks, and well 
developed in all but the most primitive family. Includes the families- 
Conocorypliidae, Olenidee, Asaphidae, Proetidae, Bronteidae, Lichadidae, 
and Acidaspidae. 
Order C. Proparia ord. n. Free cheeks not bearing the genal' 
angles. Facial sutures extending from the lateral margins of the ceph- 
alon in front of the genal angles, inward and forward, cutting the ante- 
rior margin separately or uniting in front of the glabella. Compound 
* Proc. and Trans. Liverpool Biol. Soc., x. (1896) pp. 92-102. 
t Anat. Anzeig., xiii. (1897) pp. 293-301 (28 figs.). 
t Skrift. Yidenskabs. Christiania, 1895, part i, No. 8 (published 1896), 56 pp ,. 
8 pis. § Amer. Journ. Sci., iii. (1897) pp. 181-207. 
