132 Progress in Science. (January, 
two cells of Bunsen’s battery, and the mixed gases collected with all precau- 
tion. The time taken for 1 cubic inch was 2 minutes as a mean of many 
experiments. The electrodes were then cleaned with hot oil of vitriol, 
the Bunsens freshly charged, and the 1 cubic inch of gases was furnished in 1} 
minutes ; thus showing that electrolysis is materially affected by the state of 
cleanness of the electrodes at the time. 
BIOLOGICAL NOTES. 
M. Alph. Milne-Edwards has contributed to the Academy of Sciences a very 
important paper on the Embryology and Zoological Position of the Lemuride, 
having obtained from M. Grandidier (in his last Madagascar exploration) 
specimens of four different genera of distin@ groups of these animals in the 
foetal state, and submitted them to careful anatomical investigation. His dis- 
sections prove that in regard to intra-uterine life there are essential differences 
between the Lemuride and the Simiade. In the latter the placenta is small, 
discoid, and closely connected to the uterine wall, and the umbilical vesicle is 
very minute and soon disappears. Inthe Lemuride@ (taking Propithecus as the 
highest type and nearest to the Simiadi@) the chorion is almost entirely covered 
with thick and serrated villosities, forming a kind of vascular cushion, and 
constituting a placenta which encaps the amnios, and which he names the 
placenta en cloche, in contrast with the discoidal placenta of the human race, 
and of the Simiade, the zonay placenta of the Carnivora, and the diffuse 
placenta of the Herbivora. The villosities are in large tufts towards the 
middle and upper parts of the ovum, and gradually diminish towards the 
cephalic pole, when they disappear. The caduque utérine (uterine decidua) is 
well developed and presents a corresponding arrangement. 
Between the chorion and the amnios there is a large membranous sac 
extending in the direction of the long axis of the ovum, and adhering to the 
umbilical end by a short thin pedicle. This sac is prolonged at each end into 
a kind of finger-shaped cornu, is only very slightly attached to the adjacent 
membranes, and if air is inje@ed into it, under water, we see it expand and 
its outlines become well marked. It represents the umbilical vesicle much 
less developed than in most of the unguiculata. 
The placenta presents the same character in the genera Lepilemur, Hapalemur, 
and Chirogalus. 
From this study of the fcetal membranes of the Lemurida, it follows that 
they essentially differ from those of any other mammal. This special type 
deviates further from that-presented by man, the apes, the Cheiroptera, the 
Insectivora, and the Rodentia, than from that of the Carnivora; for if we 
suppose for an instant that the caudal pole of the ovum of the dog is invested 
by the villosities of the placenta, we have an almost exaét realisation of the 
special characters of the Lemurian ovum; and it may be added that the 
arrangement of the umbilical vesicle is very nearly the same in these two 
types, while in the apes it is completely different. 
These embryological characters are in complete accordance with those fur- 
nished by the brain, the cranium, the dental system, and the hands. 
The brain of even the highest Lemuride is not developed posteriorly so as 
to cover the cerebellum,—a condition which separates them from the apes. 
The orbit, which in the apes is completely enclosed outwardly, and separated 
from the temporal fossa, communicates freely with the latter in all the Lemu- 
vide, and gives their crania a resemblance to those of the Carnivora. 
The teeth arming the lower jaw are very different in the two, the distinction 
between the canines and the incisors being much the more marked in the apes. 
The hands, in which the thumb is always well developed and usually 
opposable to all the other digits, differ from those of the apes. They are 
admirably adapted for climbing, but are unfitted for the prehension of food, 
which these animals usually seize with the mouth. The fingers, instead of 
tapering towards the ends as in the apes, enlarge at their extremities into dis- 
coidal pads, imperfectly covered by the nail; and lastly, as is well known, the 
index finger of the posterior hand terminates in a true claw. 
