mllAuSTiye^M PROGEESS OF MICROSCOPICAL SCIENCE. Ill 
visible, and on rupturing tlie sac their peculiar characteristics are 
at once manifest. Each granule or corpuscle represents a pseudo- 
navicel, all of them displaying a tolerably uniform size, which I 
calculated to average 2W00 of an inch in diameter. Some of the 
corpuscles were round, others oval, several bluntly pointed at one 
end, many curved and fusiform, not a few being almost reniform ; 
under the ^-inch objective highly-refracting points or nucleoli 
were fairly visible in their anterior, but on employing the yV^h, I 
made out nothing more respecting the contents of the corpuscles." 
The other chapters will be found full of important matter, and 
the list of authorities, bibliography, and index, show that details 
have been carefully attended to in preparing the work for the 
press. The author's remarks on " Organic Individuality," which 
he considers from an entozoologic point of view, are suggestive ; 
but we think the system of division is pushed a little too far. We 
question very much the advisability of employing so many dis- 
tinct technical terms to designate the numerous stages in the life- 
history of certain Entozoa. Helminthologists will find Dr. Cobbold's 
book a very complete supplement to his former investigations. 
PKOGKESS OF MICKOSCOPICAL SCIENCE. 
Tlie Nervous and Vascular Systems of Limulus. — M. Alph. Milne 
Edwards has been investigating into the anatomy of Limulus, and he 
has discovered some very remarkable facts in regard to the structure 
of this singular crustacean. In a paper which he communicated to the 
Societe Pliilom^tMqiie de Paris on the 26th of June, he stated that 
the researches of Van der Hoeven and Gegenbaur, while excellent in 
their way, left nevertheless a great deal to be done still. His own 
researches had been made upon the animals in the great Aquarium at 
Havre, and had been directed especially to the circulatory apparatus, 
which he says is most remarkable. He has found that a portion of 
the blood on leaving the heart passes directly through a vessel with 
resisting walls, and which includes nearly the whole nervous centres, 
and even some of the nerves, especially those of the eyes and foot-jaws, 
in such a way that the ultimate nerve-fibres, which are very loosely 
connected, are completely bathed in blood. In point of fact, instead 
of having the nerves accompanied by arteries, the arteries actually 
enclose the nerves. He also notes the presence of very numerous 
anastomoses between all parts of the arterial system. Finally, he 
states that the mode of origin of the nerves shows that the small 
anterior foot-jaws of these animals are the analogues of the antenna 
of insects and Crustacea, and th^ chelicers of Arachnida. From these 
facts and others, he is disposed to rank Limulus among the spiders. (!) 
Microsjpectroscopic Characters of Opals. — In the ' Proceedings of 
the Royal Society ' for June is published Mr. Crookes' interesting 
