98 
considerations. It is also fully illustrated by a map of the Mammoth Cave in 
Kentucky, a number of wood cuts and a series of twenty-seven beautiful litho- 
graphs, nearly all of them drawn by the author himself. The work begins with 
a description of the Mammoth Cave and others in the neighbourhood, and gives 
lists of the various animals found within them ; an account of the Wyandotte 
and other caves in Indiana, Clinton’s Cave in Utah, and one in Colorado; a 
discussion of the geological age of the caves and their inhabitants, the mode of 
colonization and the source of their food-supply. The second chapter describes 
the vegetable life of the caves, which is naturally of the most meagre description. 
Then follows a systematic description and list of the invertebrate animals found 
in North American caves, among which spiders are the most numerous. Insects 
are represented by eight species of Thysanura, four of Orthoptera, two of 
Platyptera, ten of Coleoptera and nine of Diptera—a by no means extensive 
list, but one that includes some very curious and interesting forms. The beetles 
of the genus Anophthalmus are especially remarkable and attractive to the 
ordinary entomologist. Lists are also given of the European and North American 
cave animals, and of the blind, eyeless creatures which do not live in caves, and | 
which, strange to say, almost equal in number their cavernous relatives. The 
next chapter gives a careful account of the anatomy of the brain and eyes (when 
partly developed) of certain blind Arthropods. The chief interest of the work 
culminates in the final chapter where the author discusses the origin of the cave 
species as bearing upon the theory of evolution. We have not space for any 
abstract of his views, which are well-deserving of study, but must refer the 
reader who desires fresh evidence on the subject of evolution to the work itself. 
We entirely agree with the author in his closing words: “In the case of too many 
naturalists the dogma or creed of natural selection has tied their hands, obscured 
their vision, and prevented their seeking by observation and experiment to 
discover, so far as human intelligence can do so, the tangible, genuine, efficient 
factors of organic evolution.”—c. J. S. B. 
AMERICAN SPIDERS AND THEIR SPINNING Work. A natural history of the Orb- 
weaving Spiders of the United States, with special regard to their Industry 
and Habits. By Henry C. McCook, D.D. Vol. I. Published by the Author, 
Academy of Natural Sciences of Philadelphia, 1889. 4to., pp. 372. 
The author of this sumptuous volume is so well known from his valuable 
and interesting works on the natural history of various kinds of ants, and his 
charming little book “The Tenants of an old Farm,” that any productions of his 
pen are looked forward to with lively anticipation and keen interest. We are 
quite sure that no one of the subscribers to this, his latest and greatest work, 
has been in the least degree disappointed by this first volume of the promised 
three. Though spiders are not insects, we have no doubt that every entomolo- 
gist, and indeed every lover of natural history in any of its departments, will 
deeply enjoy the perusal of this volume. We cannot give a better idea of its 
contents than by mentioning the subjects treated of. They are, first, the general 
classification, structure and spinning organs of spiders; the construction and 
armature of Orbweavers’ snares ; the characteristic forms and varieties of snares ; 
unbeaded orbs and spring snares; the engineering and mechanical skill and 
intelligence of spiders; their modes of procuring food and habits in feeding ; 
their fangs and poison bags ; their modes of nest making and its development in 
various tribes; and finally the “genesis of snares.” All these different subjects 
are fully illustrated with more than three hundred and fifty wood cuts. The 
second volume is to treat of the mating and maternal instincts, the life of the 
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