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CH JETOPODA ACANTHOCEPH ALA. 479
chsetous annelid Limnodrilus (Q. J. Micr. Sci. July 1870, and Ann. N. H.
February 1871). Brandt's memoir is finely illustrated.
9. BALBIANI finds that the egg of Strongylus gigas commences to develop
in the uterus of the female, but soon stops, further development occurring
after expulsion from the body of the host and in contact with water or moist
earth. Five or six months elapse in winter between this period and the
appearance of the embryo. The embryo can remain a year at least within
the egg without perishing. If pressed out into pure water it is destroyed;
it can only live in albuminous fluids : desiccation destroys it. A temporary
host, at present unknown, is (the author concludes) occupied by the developing
embryo, whence it migrates into its final host.
10. MARION describes, in ninety pages, illustrated with eleven plates, a
number of non-parasitic marine Nematoids. Twenty-two supposed new
species are described; and a special portion of the work is devoted to
anatomical considerations. It is exceedingly remarkable that the author
makes no reference whatever to the elaborate papers by Dr. Bastian on the
very same subject, published in the Linnean Society's Transactions and the
Philosophical Transactions of the Royal Society. French naturalists cannot
expect their work to secure respect when they ignore so completely the
work of others.
11. ZURN investigates the question of the occurrence of Trichina as a
parasite in insects. He allowed flies to lay their eggs in some trichinized
pig's flesh, and after examining 150 of the maggots found no indication
whatever of their being affected with Trichina. He suggests that cases of
viviparous reproduction, such as that of the Cecidomyia-laxvee, may have
given rise to the notion that insects are liable to Trichiniasis.
12. METSCHNIKOFE discusses some of the forms described by Greet in a
recent paper, which he has also met with in the Mediterranean. He considers
that Greef has mistaken the testes of Echinoderes for ovaries, and the
spermatozoa for embryos. Ziirn, of Jena, has recently shown that in the
nematoid Spiroptera circinnata the converse mistake had been made by
Muller, of Vienna, the young embryos of this viviparous form having been
taken by him for spermatozoids.
13. The Filaria was found in the pericardium of H. bennettii. Its anatomy
is sketched.
14. SCHNEIDER took the eggs of the Echinorhynchus gigas from the pig, fed
the larva of Melolontha vulgaris with them, and readily succeeded in watching
the development of the eggs. With the larva of Tenebrio molitor and with
Asellus aquaticus he did not succeed. He found the embryo of Echinorhynchus
gigas easier to observe than the species which have been studied by
Leuckart and by Greef, because of its larger size. The difficulty of understanding
the Echinorhynchi lies, he considers, not in a want of knowledge as
to them themselves, but in the absence of once-existing intermediate forms.
Their structure may be best explained by regarding them as double animals,
the proboscis-apparatus being one animal and the sexual apparatus another,
whilst the body-wall is common : both units are mouthless. The kind of
aggregation seen in the Bryozoa is parallel to this. Such a view of the
morphology of the Echinorhynchi is favoured by their developmental history,
of which Schneider promises shortly a fuller account.
15. VAN BENEDEN (senior) extends his classification of parasites, giving