ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
433 
-degree of development attained by their nervous system. Thus there 
is a cellular lens contained in a pigmented retinal cup, analogous to the 
vertebrate structure. 
The memoir contains a short account of the three families Cliaryb- 
deidae, Chirodropidae, and Tripedalidae, and a detailed description of 
the structure of Charybdea Xaymacana, with a particular account of the 
vascular lamellae and the nervous system. 
Some Medusae from Australia.* — Prof. A. Agassiz and Mr. A. G. 
Mayer describe Desmonema rosea sp. n. and Crambessa mosaica Haeckel, 
obtained on a recent visit to the Great Barrier Reef. 
Actiniaria from East Spitzbergen-t — Dr. C. R. Kwietniewski de- 
scribes Allantactis parasitica Danielssen, Chondr actinia digitata O. F. 
Muller, Ch. nodosa Fabricius, Actinostola spetsbergensis Carlgr., A. waleri 
sp. n., and Leiotealia spetsbergensis sp. n. 
The discovery of the species of Leiotealia is interesting, since it has 
hitherto been recorded only from the Antarctic, but there are other 
■cases of equally wide range, e. g. Actinostola callosa , Actinauge verrillii 
McMurrich, and A. fastigiata McMurrich. The author also notes the 
occurrence of brood pouches in Arctic anemones, as Y errill first pointed 
out. There are two modes : — in the one case the embryos develop in 
the gastric cavity of the mother ; in the other case there is a special 
cavity in the body-wall. The need for these pouches is perhaps to be 
found in the limitations which the ice imposes on the superficial 
Plankton. 
Studies on Madreporaria.J— Mr. H. M. Bernard maintains that the 
Madreporarian genus Alveopora agrees in all essentials of skeletal struc- 
ture with the Palaeozoic Favosites , the little known Cretaceous genus 
Koninckia helping to link them through the long interval of time. 
The skeleton of Alveopora is at a very low level of development — like 
a survival, — and is far away from that of the Poritidae with which the 
genus is usually classed. 
“ The Madreporarian skeleton may be described as the rigid secretion 
of the basal portion of the columniform body of a polyp into which the 
flexible upper portion may be invaginated. In its earliest developments 
■a simple cup, it has become complicated in various ways : primarily, by 
the development of radial infoldings of the stiff external wall, com- 
parable with the infoldings of the chitinous cuticle of Arthropods ; 
secondarily, (1) by further complications of these infoldings, so as to 
form an intricate 4 internal ’ skeleton, which may render the primitive 
external cup unnecessary, and hence lead to its becoming vestigial ; (2) 
by a process of repeated sheddings of the external hard secretions, and 
the formation of new ones across and among the 'existing 4 internal ’ 
skeletal structures (dissepiments and tabulae).” The growing soft parts 
may also overflow the primitive rigid cup, and the bagging thus occa- 
sioned may reach the substratum and widen the base, or may merely 
hang down, secreting in so doing a folded rim to the cup (“ eutheca ” 
of von Heider). Along the lines suggested by these conclusions, the 
* Bull. Mus. Zool. Harvard, xxxii. (1898) pp. 15-9 (3 pis.). 
f Zool. Jahrb., xi. (1898) pp. 121-40 (1 pi.). 
% Journ. Linn. Soc. (Zool.), xxvi. (1898) pp. 495-516 (1 pi.). 
