Bibliographical Notices. 247 
most marked degree the normal and typical forms of the Fish. 
The salmon and herrings of our waters are, of all fishes, those 
which have best preserved the original forms; they are also 
those which have the longest known pedigrees. 
The great Ctenoid division, so varied and important at the 
present day, has no known root before the Cretaceous epoch. 
It is represented by a certain number of types bound together 
by numerous common characters, especially of general appear- 
ance and external covering. These types form the base of a 
large bundle or knot, the various threads of which have become, 
through successive ages, gradually more and more differentiated 
and widely removed from each other and the common stock. 
The third group which has played an important part in the 
history of these Teleosteans is that of the Hoplopleuride, more 
isolated than the preceding ones. There is no indication of this 
group in the Jurassic period, nor any continuation of it in the 
Tertiary. 
These three groups form almost the totality of the Teleosteans. 
There would now only remain to add, in the present state of our 
knowledge, some few isolated genera with whose history we are 
but incompletely acquainted, and which would seem to be sub- 
ordinate to the preceding ones as much on the ground of this 
isolation as on that of the small number of individuals repre- 
senting them. 
BIBLIOGRAPHICAL NOTICES. 
A History of British Sessile-eyed Crustacea. By C. Spence Bate 
and J.O. Westwoop. Part XIII. 8vo. Van Voorst. London, 
1866. 
THE appearance of a new part of this valuable work, after an in- 
terruption of nearly three years (the twelfth part was published in 
August 1863), leads us to say a few words about it, in the hope that, 
however we may regret such delays, the interval in the present case 
may have given time for the training of a new school of students, to 
whom such a book as this will be welcome. 
In the first volume, completed in 1863, the authors nearly finished 
their descriptions of the British species of true Amphipoda, leaving 
only the Hyperine forms for the commencement of the second vo- 
lume. The Amphipoda aberrantia of Mr. Spence Bate, including 
the Lemodipoda of Latreille, with the addition of the Dulichiide of 
Dana, are completed in the part just published, which also contains 
the general remarks on the Isopodous order. 
In form, the Crustaceans here described are among the most sin- 
gular of the inhabitants of the sea, although their relationship to the 
true Amphipoda is so evident that one feels surprised they could 
