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 Hoplopleuridse, more 

 isolated than the preceding ones. There is no indicatien 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. Westwood. 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 Arnphipoda, leaving 

 only the Hyperine forms for the commencement of the second vo- 

 lume. The Arnphipoda aberrantia of Mr, Spence Bate, including 

 the Lcemodipoda of Latreille, with the addition of the Dulichiidce 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 



