260 
POPULAR SCIENCE REVIEW. 
have been issued to the subscribers ; works which it would have been im- 
possible for any publisher to bring out in the same style without certain loss ; 
and we are glad to take the opportunity of the appearance of the second 
volume of Mr. Brady’s book on the British Free and Semi-parasitic Cope- 
poda to remind our readers of the existence and activity of this Society, 
which certainly merits a larger share of patronage than would appear to fall 
to its lot. This is not the place to give a list of its publications, but we 
may cite the magnificent work of Alder and Hancock on the Nudibranchiate 
Mollusca, Forbes’ Naked-eyed Medusae, Professor Allman’s Freshwater Poly- 
zoa, Mr. Blackwall’s British Spiders, and Mr. Darwin’s Monograph of the 
Cirripedes, as showing how much naturalists are already indebted to the 
Bay Society. 
Among the earlier volumes published by the Society was Baird’s Natural 
History of the British JEntomostraca, an excellent and standard work, founded 
to so great an extent upon the author’s personal investigations that although 
it is now somewhat out of date it must always hold its position as a book of 
reference. It was published in 1850 ; and the best proof of the vast strides 
that have been made in this department of Zoology, of late years is to be 
found in the fact that Mr. Brady has now devoted two octavo volumes to 
the description of the members of only one of the six orders recognized by 
Baird. The truly parasitic forms, whose alliance with the crustaceans de- 
scribed by Mr. Erady is, in many cases, established only by the investigation 
of their development, were placed by Baird in a separate division of the 
Entomostraca ; and this distinction is still maintained by some high authori- 
ties, so that his Copepoda include precisely the free-swimming and semi-para- 
sitic (or commensal) forms which form the subject of these volumes. 
Of his Copepoda, Baird describes and figures only thirteen species, but in 
the case of the well-known freshwater Cyclops he cites three varietal forms, 
so that we may reckon that he recognized fifteen forms in the order. Mr. 
Brady, however, describes fourteen species of the genus Cyclops , as now 
restricted, whilst the total number of British Copepods with which he expects 
to have to deal in the execution of his present task, amounts to at least 151. Of 
these, 134 are treated of in the volumes before us, the remainder, consisting 
of three families of somewhat aberrant and semi-parasitic forms, will form a 
third volume, which will also contain a general sketch of the anatomy and 
physiology, and development of these organisms. In his Introduction, Mr. 
Brady gives short directions as to the best modes of collecting, examining, 
and preserving the Copepod Crustacea. 
Of the systematic part of the work, considering the reputation of the 
author, it is scarcely necessary to say much. As we have already remarked, 
he differs somewhat from certain other writers in his views as to the affini- 
ties of the free and parasitic Copepods, and this, to a certain extent, influ- 
ences his opinions as to the classification of the former; but only with 
regard to certain doubtful forms, as to which an absolute agreement be- 
tween different geologists is scarcely to be hoped for. In every respect the 
work is most carefully executed, and it cannot fail to prove of the greatest 
advantage to the students of our British fauna. The plates, of which there 
are in all eighty-two, furnish outlines, and sometimes coloured figures of the 
species, with copious illustrations of the structure of those parts which are 
