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cases are very badly printed. The book classifies animals according as they 
(1) burrow in tbe ground; or (2) suspend their homes in the air; or (3) 
build them of sticks, mud, stone, and so forth; or (4) make their habita- 
tions under the water ; or (5) live socially in communities ; or (6) are para- 
sites upon other animals or plants; or, lastly (7), those which build on 
branches. His account of the habits of some animals is very interesting. 
Thus, speaking of the curious robber-crab of the Indian Ocean, a creature 
whose gills are kept moistened by a store of water, which enables it to live 
for a whole day of twenty-four hours without a visit to the ocean, he 
quotes from Mr. Darwin, and tells us that the species “seizes upon the 
fallen cocoa-nuts, and with its enormous pincers tears away the outer 
covering, reducing it to a mass of ravelled threads. This substance is 
carried by the crabs into their holes for the purpose of forming a bed, 
whereon they can rest when they change their shells ; and the Malays are 
in the habit of robbing the burrows of these stored fibres, which are ready 
picked for them, and which they use as junk When the crab 
has freed the nut from the husk, it introduces the small end of the claw into 
one of the little holes which are found at one end of the cocoa-nut, and, by 
turning the claw backwards and forwards, as if it were a bradawl, the 
crab contrives to scoop out the soft substance of the nut.” If we mistake 
not, an exquisite woodcut accompanied this account in the parent volume, 
which we wish the author had introduced into this. As we have already 
said, the book is a good one, but the illustrations are bad ; and that, 
in these days of elaborate woodcuts, is a fault for which we think Mr. Wood 
cannot be blamed too much. Description is very good in its way, but 
illustration fixes it on the mind for ever. 
THE STUDENT’S GEOLOGY* 
T HIS, which appears a new work, and which in point of the novelties of 
geology with which it abounds, is really so, is nevertheless but a new edi- 
tion of a work which every biologist is already familiar with — the “Elements” 
of Geology. The “ Elements ” was, as the author states, out of print 
in 1868, and he set to work with the idea of bringing out a new edition. 
But various influences were at work upon him to induce him “not to repeat 
those theoretical discussions, but to confine himself, in the new treatise, to 
those parts of the 1 Elements ’ which were most indispensable to a beginner.” 
This was, in fact, to revert to the first edition of his work. It was a 
difficult task : many chapters had of course to be recast, figures of particular 
specimens had to be cancelled and replaced by others, and additional illus- 
trations had to be brought in. Nevertheless, Sir Charles Lyell set to the 
task, and in bringing out the present new series — “ The Student’s Elements 
of Geology ” — he has discharged a task for which he must receive the grate- 
ful thanks of all who study geology, and of all those who wish to see the 
* “ The Student’s Elements of Geology,” by Sir Charles Lyell, Bart., 
F.R.S. London : John Murray, 1871. 
