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stages, called Pedogenesis by Von Baer. The formation of 
the egg-like reproductive bodies commences in the larve; 
but the eggs are not extruded until the insect has passed 
into the pupa state. It appears that in the spring the larve, 
produced in the ordinary way from eggs, grow rapidly, and 
after the third change of skin attain their full size, and show 
distinct traces of the pupa within them. The eggs are pro- 
duced direct from the pupa in this condition. In the autumn 
the course of development during the preparatory changes is 
precisely the same; the pupa, however, changes into the 
imago, which deposits the eggs, probably after copulation, in 
the ordinary manner. ‘The mode of development of the eggs 
and ovaries, and that of the embryo in the egg, are described 
by the author at considerable length, and illustrated by good 
figures. The eggs are developed in the same way, both in 
the spring and in the autumn, although in the one case they 
will be deposited by the pupa, and in the other by the 
imago; and as they present no difference in their structure, 
the author regards them all as eggs, and rejects the distinc- 
tion into ova and pseudova. He seems inclined to adopt the 
notion that the supposed cases of parthenogenesis may be 
due to self-fecundation.— The Academy. 
Young Stages of the King Crab.—It is hardly to the credit 
of our American brother naturalists that the development of 
the interesting and peculiar form Limulus has hitherto not 
been worked out by them, seeing that they are favoured by 
its presence in abundance on their coasts. Mr. Lockwood 
and Dr. Packard have made a step in the right direction by 
observing the later changes which the embryo undergoes. 
They find that in accordance with Haeckel’s law of indivi- 
dual development epitomising paleontological development, 
the young Limulus agrees in its form with those paleozoic 
allies of the genus which have been worked out by Mr. Henry 
Woodward. These writers, whose observations appear in 
the ‘ American Naturalist,’ do not, however, appear to have 
worked at the earlier developmental changes, at the various 
coats of the embryo in its successive periods of intraovular 
development, which have a surpassing interest at this time 
in connection with Dr. Anthon Dohrn’s and Dr. Edouard 
Van Beneden’s researches and speculations on the phylogeny 
of Arthropoda. ‘The eggs are said to possess great vitality— 
would it be possible to obtain some in this country? We 
shall be very glad to enter into correspondence with any one 
who will suggest a means of obtaining, or undertake to pro- 
cure a supply of these ova. 
Microzoology. The Siliceous Sponges.—Dr. Oscar Schmidt 
