38 Fossil Fishes. 



" From this state of things, and from the manner in which I have 

 been obliged to study living fishes, that I might compare them with 

 fossil ones, a great advantage has resulted in the complete indepen- 

 dence I was required to maintain concerning all the former reputed 

 alliances of different fishes ; because the great number of new species 

 which have been discovered since the commencement of the present 

 century, for the most part represented in the Rcgne Animal of Cu-^ 

 vier, and which it was necessary to insert in the groups of the natu- 

 ral families of this class, has caused all the alliances proposed by the 

 older Ichthyologists entirely to disappear. In afresh reviewing their 

 characters, I have been led to adopt a classification w 7 hich differs 

 considerably from any arrangement which has hitherto been propo- 

 sed, and which is founded upon important considerations which have 

 hitherto been neglected. 



" It admits of no doubt, that one of the distinctive characters of 

 the class of fishes, consists in the skin being possessed of scales of a 

 peculiar form and structure. This covering, which protects the an- 

 imal externally, has, according to all the observations 1 have made 

 up to the present moment, the most direct relation to its interior or- 

 ganization, and to the external circumstances in which the animal is 

 placed. So that, in this point of view, the scales acquire a primary 

 importance, and may be regarded as a superficial reflection of all that 

 passes within and around the fish. Accordingly, upon attentively- 

 examining them, I have found that fishes may be arranged in an or- 

 der much more natural than any hitherto proposed, by allowing our- 

 selves to be regulated by the structure of the scales. Acting on this 

 principle, I have established four orders, which present some resem- 

 blance to the great divisions of Artedi and Cuvier, but one of which, 

 hitherto almost wholly unknown, is nearly exclusively formed of ge- 

 nera, the species of which are found solely in the older strata of the 

 crust of the globe. These four divisions are — the Placoides, which 

 includes all the cartilaginous fishes of Cuvier, with the exception of 

 the Sturgeons ; the Ganoides, which comprehends more than fifty 

 extinct genera, and with which it is necessary to ally the Plectogna- 

 thes, the Syngnathes, and the Acipenser ; the Ctenoides, which are 

 the Acanthopterygiens of Cuvier and Artedi, to the exclusion, how- 

 ever, of all those which have smooth scales, and including: with them 

 the Pleuronectes ; and, lastly, the Cydoides, which are principally 

 the Malacopterygiens, but which likewise comprehend all the fami- 

 lies which are excluded from the Acanthopterygiens of Cuvier, and 



