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POPULAR SCIENCE REVIEW. 
ZOOLOGY AND COMPARATIVE ANATOMY. 
Preservation of the Young among Crustacea. — M. Eugene Hesse lias made a 
singular discovery of a mode in which the young are preserved among some 
of the parasitic entomostraca. The larvae are united to the mother’s "body 
by a natural cord or fibre, which passes from the parent’s body to the frontal 
appendage of the young animal. This fibre does not play the part of an 
umbilical cord, but it preserves the young from danger when the parent 
migrates from one fish to another. 
A Species of Silk-spider. — An American journal, reports that a specimen 
of the above was found by Dr. Wilder, while in camp on Folly Island, in 
Charleston Harbour. From the body of one of these insects in one hour and 
a quarter he wound 150 yards of yellow silk. The next year another officer 
wound from 30 spiders 3,484 yards, or nearly two miles of silk. A single 
thread of this is strong enough to sustain a weight of from 54 to 107 grains. 
The species was shown to Professor Agassiz and other naturalists, to whom it 
was new. It is proposed to cultivate it. — Vide The Boston Journal. 
The Mode of Formation of lanthincts Float has been discovered by M. 
Lacaze-Duthiers, whose paper on the subject was translated in a late number 
of the Annals of Natural History. The float consists of air-bubbles, which 
the creature imprisons by throwing off a mucous secretion from the anterior 
extremity of its foot. The animal cannot swim without the float, which it 
thus artifically constructs. 
Geneagenesis among the Cecidomyas. — The strange mode of reproduction 
among the Cecidomyas, which has been demonstrated by Herr Wagner, has 
led to some controversy among European naturalists. Indeed, the investiga- 
tions referred to may be regarded as some of the most important, in respect to 
the results, that have been made during the present century, for they in some 
measure bear out the views of M. de Quatrefages on what is erroneously styled 
Parthenogenesis , and corroborate the doctrine laid down by Professor Huxley 
in his memoir on the reproduction of the Aphis. Of course, we allude only 
to the facts elicited by Herr Wagner’s researches, and not to his method 
of viewing or explaining them. Our present motive in directing attention 
to them is because of a paper which has been presented to the Royal 
Academy of St. Petersburg by Von Baer. In this the author combats 
several existing theories without throwing much light upon the obscure 
question of geneagenesis , and proposes a new term, pcedogenesis, for all those 
processes by which an immature creature, such as a larva, reproduces off- 
spring. 
The Anatomy of the Foot and Leg of the Phalanger has been carefully 
studied by M. Alix, who read a paper on the subject at a late meeting of the 
Philomathic Society of Paris. The paper contains an infinitude of anatomical 
details concerning the relations of the bones and muscles of the foot and leg, 
but is too technical for an abstract in these pages. — Vide L’lnstitut, May. 
Forthcoming Treatise on Exotic Birds. — A splendidly-illustrated treatise 
