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270 PROCEEDINGS OF THE SOCIETY OF 
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to experiments conducted in London, by M. Marcet, with a view of determin- 
ing whether the toxic action of alcohol makes its impression on the brain 
through the medium of the circulation or of the nerves. The experiments in 
question show that the circulation is the essential intermediary. Our colleague 
further laid before us the result of researches, in which he has been engaged 
for three years, on the evolution of arachnida in the egg, and accompanied 
his developments with several plates. A detailed analysis of this remarkable 
memoir would involve so many particulars, and necessitate the use of so many 
technical terms, that I am with reluctance compelled to forego it. The result. 
of the phenomena imports that the embryo originally rolled up on the back is 
in the end rolled up on the belly. To this memoir M. Claparede added some 
expressions on the utility of these embryological investigations in the comparison 
of the appendages of the spider with those of other arthropods. He shows 
that the protognaths or forciples of the spider are homologues of the antennz 
of the larvee of insects and of the antennze of the second pair of the crustacea, 
while the deutognaths are homologues of the mandibles of the crustacea and 
of insects. M. Claparede also presented us with some drawings of animals but 
little known, which he had observed in the Hebrides. The first of these are 
representations of two species of worms of the group of the Sipunculoide. 
Another represents an <Actinotrocha branchiata, a marine animal for which 
hitherto no place has been found in any division of the animal kingdom. M. 
Claparedé suspects this strange looking creature to be the larva of a worm. 
Lastly, our colleague gave us an account of the physiological researches of M. 
Voit in regard to the pearl Unio, and explained the reasons which render doubt- 
ful the respiratory functions of the pretended branchia of the Lamellibranch, 
M. de Candolle presented, on the part of M. Guerin-Menneville, a report on 
the attempts made tor the acclimatation, in France and Algiers, of the silk-worm 
of the Ailanthus, ( Bomby@ cynthia.) 
M. de Saussure continued his communications on the natural history of 
Mexico. He spoke first of the Vampiride, cheiropterous animals with a pecu- 
liar membranaceous foliation seated on the nose, and showed, as specimens, 
those particularly of the Mormopsis Blainvillei, which, till now, were found in 
no museums but those of London and Berlin. He afterwards described a Cen- 
turio, with a face singularly distorted, and withal more obtuse than that of any 
of the Mammals, man included, but with a skull so greatly flattened as to pro- 
duce a resemblance to the frog. M. de Saussure further presented a Coati, of 
which a new species of late has been erroneously formed. 
From M. Humbert the Society received some very interesting statements 
with respect to his explorations in Ceylon; and first, in regard to many species 
of terrestrial Planariz, of which he exhibited drawings, and several of which, 
discovered by M. Humbert, are distinguished by the malleiform or crescent- 
shaped enlargement of their anterior portion. M.Claparede followed this com- 
munication with some remarks on the anatomy of one of these species. M. Hum- 
bert proceeded to give some particulars respecting the land leeches, which are 
very common, and not a little inconvenient in certain parts of the island—so 
common, indeed, that it is impossible to keep goats in such places. At another 
meeting he gave an account of the general aspect of the ornithological fauna of 
Ceylon, and exhibiting numerous specimens, described the habits of the curious 
birds which he. placed before us. 
I shall have coneluded the portion of my report which relates to zoolog 
when I mention the memoir read at our last session, by M. Victor Fatio, on the 
different varieties of frogs which frequent the environs of Geneva. In this 
memoir, which is accompanied with colored plates, the author describes, under 
the name of Rana gracilis, a new species found in the marshes of Puplinge, 
and produces some fine specimens of it. 
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