116 
EEYIEWS. 
Tlie Ijand and Fresliivater MollusJcs indic/enous to, or naturalized in, the 
British Isles. By Lovell Keeve, F.L.S. London : Keeve and Co. 1863. 
One thing must be admitted of Mr. Reeve's boots : they are always 
got out with great care and taste. The volume before us is another ex- 
ample, and is, typographical 1}^, and in size, paper, and illustrations, the beau 
ideal of what such a book should be. It is of most handy and convenient 
size, clearly printed, and illustrated with very characteristically and very 
nicely executed woodcuts. The matter is also good — we need scarcely say 
that of Mr. Reeve's con chological labours — and very conveniently arranged. 
First, is an Alphabetical List of Species, then a Systematic List, follow ed 
by an Analytical Key, displaying at a glance the natural groups into fami- 
lies and genera, and the characteristic features of each species. A map of 
botli hemispheres shows the boundaries of the Caucasian province, over 
which the British species range, and the position of this area in respect to 
other areas, and the general terrestrial system. Of the broad, general 
divisions of molluscan distribution, Mr. Eeeve recognizes in the eastern 
hemisphere the following provinces : — the Caucasian, the West African, 
South African, Malagan, Australian ; in the western hemisphere — the 
!North American, Columbian, Brazilian, Bolivian, and Chilian provinces. 
After a brief description of the appearance, condition, and extent of the 
British fauna, we pass on to some 240 pages of descriptive matter, giving 
the accepted names of each species, its synonyms, and its characters and 
habitats. 
So important as fossil shells are in the palseontological history of the 
earth's past states, a good work like the present, on British shells, cannot 
fail to be of service to the geologist. Other books, such as Hanley and 
Forbes's ' British MoUusca,' exist, but such an elaborate and costly work is 
much beyond the attainments of ordinary students ; w hile Mr. Reeve's 
less pretentious and inexpensive book contains all essential information. 
It is by the practical study of Bj-itish shells that those British geologists 
who are not travellers must obtain their knowledge for the comparison of 
fossil mollusks, and the comprehension of the probable conditions of their 
ancient existence. The concluding chapter of ^Ir. Reeve's book, " On the 
Distribution and Origin of Species," will be read, however, by the practical 
geologist and naturalist with much interest. We all remember the late 
Edward Forbes's theories of Centres of Creation, and how fully the idea of 
species taking their origin each from a single pair, the progeny of which 
spread around and around the birthplace of its progenitors into wider and 
w ider geographical areas, was accordant with popular notions. Mr. Reeve 
takes a very opposite view, and pleads for a plurality of originating in- 
dividuals on the following important grounds : — Firstly, that land species, 
with greater facilities of migration than freshwater, are less widely and 
evenly diffused; secondly, that land and freshwater species of opposite 
hemispheres are not always representative, but sometimes identical ; and, 
thirdh% that the range of land and freshwater species over areas or zoolo- 
gical provinces indicated by uniformity of type, is not arrested by the in- 
tervention of seas. 
The following extract will sulEce to show the important bearing of this 
chapter on geological science : — " The doctrine of the migration of all the 
individuals of a species from a single parent (or pair) involves the con- 
clusion, that species permanent, as I think, in their character, and immu- 
table, diminish in number in their march from the specific centre of a pro- 
