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POPULAR SCIENCE REVIEW. 
which had been exhibited at a recent meeting of the Microscopical Society. 
They were affixed to the skin of the fowl by the proboscis, so that only 
the tails were visible outwards. 
Embryology of the Ctenophorce . — The development of certain jelly-fishes 
(Ctenophorse) belonging to the genera Idyia and Pleurobrachia has been 
elaborated with great care and beauty of illustration by Mr. A. Agassiz, in a 
memoir which has been recently published in the United States of America. 
He gives, says the “American Naturalist ’’for January, a connected account 
of their history from the earliest stages in the egg until all the features of 
the adult appear. While the mode of segmentation of the yolk is extra- 
ordinary, the embryo attains the adult form without any metamorphosis, 
the changes being very gradual. Mr. Agassiz’s observations, with the pre- 
ceding ones of Muller, Gegenbaur, Kowalevskv, and Fol, give us a tolerably 
complete view of the mode of development of this order of jelly-fishes. 
These Ctenophorse on our coast spawn late in the summer and fall. The 
young brood developed in the autumn comes to the surface the following 
spring nearly full-grown, to lay their eggs late in the summer. The 
autumn brood most probably passes the whole winter in deep water, and 
it must take six to eight months for the young to attain their maturity. 
