34 " Fossil Fishes. 



readers, especially as our own series of the livraisons of this work is 



interrupted. 



If the general reader should be repelled by the new names which 

 the author has found it necessary to introduce, he will find no diffi- 

 culty in going along with the wonderful development of geological 

 formations, in which the numerous races of fishes are found, and 

 with the progressive alteration in their forms in the different epochs. 

 Fishes begin very early even below the coal, soon after the slaty 

 rocks of the primary family, as early as the grauwacke, if not be- 

 fore ; and they continue (changing however their races,) as the crea- 

 tion advances, quite to our own times. All, that sober minded geol- 

 ogists believe of the epochs of deposition and formation, and of the 

 extent of time, is fully established by the history of fossil fishes* 



alone. 



Work of Agassiz on Fossil Fishes.f 



Of the great work on " Fossil Fishes, 55 by Professor Agassi z, four 

 numbers have already appeared, eminently distinguished by the ac- 

 curacy and elegance of the engravings, and the very interesting na- 

 ture of the letterpress. The fifth number is finished, and will ap- 

 pear during the course of next month. 



In the first number our author informs us, that by an attentive ex- 

 amination of the scales, fishes may be divided into orders more natu- 

 ral than those hitherto adopted by naturalists. In this manner he 

 has established four orders, which bear some relation to the .divis- 

 ions of Artedi and Cuvier, but one of which, hitherto misunderstood, 

 is almost exclusively composed of genera whose species are found 



only in the older formations of the crust of the earth. These four 

 orders are the following ; 



" Order I. Placoides. — The tribes of this order are so named 

 on account of the irregularity of the solid parts of their integuments; 

 these are, masses of enamel, often of considerable size, or sometimes 

 reduced to small points, as in the shields of the ray and the different 



* We again call on the American public to patronize tbis great and difficult work, 

 which ought to be in every public library, and in those of opulent individuals: the 

 cost is about $100. 



t Recherches sur les Poissons Fossiles, in quarto livraisons ; the plates in folio. 

 The booksellers in London who furnish the work, are Black & Armstrong, 2 Ta- 

 vistock Street, Covent Garden, and J. B. Bailliere, 219 Regent Street, London. 



