no 
POPTTLAK SCIENCE EETIEW. 
impregnation and consequently no developmental changes. From these 
facts it seems almost certain that impregnation takes place in the head, 
and, unless both sexes are present there, the brood fails. It is also probable, 
on the supposition that these worms are migratory, that it is in the head of 
the Anhinga the sexual organs are developed, the young arriving there in 
an immature state. 
The Development of the Nervous System in the Annulosa. — A very valuable 
paper on this subject appears from the pen of Mr. B. T. Lowne (of Middle- 
sex Hospital), in the Monthly Microscopical Journal ” (December, 1872). 
Before passing in review the various facts and arguments which he advances, 
he gives a brief account of what Dr. Metschnikoff has done. According to 
the observations of that author, the first trace of the embryo scorpion is a 
longitudinal groove in the blastoderm : this groove afterwards disappears for 
a time, but subsequently becomes visible again as a deep groove, on either 
side of which the nerve ganglia of the ventral chain appear as thickenings 
of the external layer of the blastoderm. Nerve fibres are next seen pene- 
trating the median layer, or mesoblast. The mesoblast splits, as in verte- 
brates, to form the body cavity, its inner layer becoming incorporated with 
the inner or visceral layer to form the alimentary canal. In connection with 
these observations, the remarkable internal skin growths which support the 
principal nerve centres of insects and crustaceans are of the highest signifi- 
cance, as it is quite clear that they are the highly-developed remains of the 
primitive fold in which the nervous system is formed. One of the most 
striking circumstances in the development of the nervous system is the 
bifurcation of the neural groove and chain at its anterior or cephalic end, so 
that it embraces the mouth and pharynx in a kind of fork, the anterior ex- 
tremity of which gives origin to the great preoesophageal or prestoma 
ganglia. 
Liquid Emitted hy the Larva of a Species of Cimhex. — In the “ Archives 
Neerlandaises des Sciences,” November 4, 1872, M. A. J. Van Rossum, in 
the beginning of a paper on the above, communicates some entomological 
particulars relating to the larvae of the Tenthredince, genus Cimhex, which, 
provided with small lateral apertures, emit through these, with compara- 
tively great force, a coloured fluid to protect themselves from the attacks of 
ichneumons, birds, &c. This fluid, collected by the author from the living 
larvae, has been chemically investigated, and found, while exhibiting a dis- 
tinctly alkaline reaction, to be mainly a protein or albumenoid compound, 
which behaves with reagents very much like white of egg. As regards the 
nature of the colouring matter, it is probably chlorophyll, or some modifica- 
tion thereof. The liquid experimented with was that from the larvae of 
Cimhex connata and Cimhex sylvarum. The author thinks that the fluid 
acts as a means of defence more by reason of its viscosity than by reason of 
its weak alkalinity. 
The Death of M.Pouchet. — The Evening Standard ” of Saturday, Decem- 
ber 21, 1872, announces the death, at Rouen, of Dr. Pouchet, aged 72, 
after a severe illness. He was the author of numerous scientific works. 
His “ Th^orie de TOvulation Spontanee ” obtained in 1845 the great prize 
of experimental physiology, viz. 10,000f., awarded by the Academy of 
Sciences. He had lived just long enough to complete an important treatise 
on birds, which had occupied him several years. 
