528 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
total of about 1000 species of Anura, about half belong to America, 
more than a quarter to Asia, over a sixth to Africa, and at most sixteen 
species to Europe. There are 57 species in Madagascar, 21 in Celebes, 
125 in British India, and 135 in Mexico. The three genera Bana , 
Bufo, and Hyla are almost cosmopolitan. But we cannot do more than 
direct attention to this interesting paper. 
Marine Fauna of Brittany and the Gulf of Lyons.* — Dr. G. 
Pruvot makes a comparison between the marine faunas of these two 
areas. He distinguishes, — (1) a littoral region, with a sub-terrestrial 
and a strictly littoral zone, the latter divided into three sub-zones or 
horizons ; (2) a coast region, with two zones ; and (3) a deep region, 
also divided into two zones. We do not know how to summarise the 
author’s paper within our narrow limits, but it is much too important 
to be left unrecorded. 
Plankton of Puget Sound.f — Messrs J. I. Peck and N. R. Har- 
rington have found, in regard to Peridinium , Coscinodiscus , Melosira , 
Copepods, and Nauplii, that the surface strata present the greatest 
numbers of living individuals, and furnish the most favourable, although 
irregular, conditions for the growth and reproduction of these organisms. 
In the case of the large diatoms, burdened with their siliceous case, 
there is a relatively rapid sinking into the strata beneath, and in other 
diatoms the conditions of growth seem to be well fulfilled in the lower 
strata. All the forms treated of except the Copepods were found alive 
down to 112 fathoms, probably the lowest depth to which the method 
of quantitative estimate has been carried. 
Plankton of Rivers. — Dr. C. Zimmer J distinguishes (a) the 
“ autopotamic ” plankton, restricted to flowing water, and consisting ex- 
clusively of algae, unless perhaps Tetramastix opoliensis Zach. ; (b) the 
“ eupotamic ” plankton, occurring in standing as well as in flowing 
water ; and (c) the “ tychopotamic ” plankton, of exceptional occurrence 
in rivers. A list of observed forms is given, but as yet it is a short 
one. 
Herr B. Schroder § ’ also discusses the plankton of the Oder, and 
compares it with that of the pond (fed by the river) in the botanic 
garden at Breslau. 
Common Eel in the Open Seas.|| — M. Leon Vaillant notes that a 
specimen of Anguilla anguilla L., a yard long, was taken by Captain 
Chaves from the stomach of a cachelot-whale, which seems to show that 
this remarkable fish goes far out to sea. If we understand the last 
paragraph aright, the author does not seem to be aware of Grassi’s 
results. 
Biological History of Carbon.^" — A. Bach completes an essay on 
this subject, which shows at least the incompleteness of our knowledge. 
By a process analogous to electrolysis, C0 2 is decomposed in the green 
plant ; formic aldehyde is formed and is polymerised to give rise to 
glucose; thence, perhaps by some ferment, other sugars and starch 
* Arch. Zool. Expel*., v. (1897) pp. 511-660 (6 pis.) maps and curves, 
f Biol. Centralbl., xviii. (1898) pp. 513-22. 
t Tom. cit., pp. 522-4. § Tom. cit., pp. 525-35 (1 fig.). 
|Comptes Rendus, exxvi. (1898) pp. 1429-30. 
f Arch. Sci. Phys. Nat., v. (1898) pp. 520-35. 
