374 FISHES. 



jirst division includes fishes which have both appendages ; the 

 second those which have a branchial operculum and no mem- 

 brane ; the third those which have simply a membrane ; and the 

 fourth those which have neither operculum nor branchial mem- 

 brane. Each of these groups is further divided into four orders, 

 viz. Apodes, Jugulares, Thoracici and Abdominales, borrowed 

 from the Linnsean arrangement, making in the whole thirty-two 

 orders, of which, as Dr Fleming remarks, fifteen have no exam- 

 ples in nature. 



Lacepede has preserved all the generic terms used by Lin- 

 naeus, and has formed many others to characterize the new 

 groups which he had found it necessary to establish. But these 

 generic terms are not alweiys happily applied ; and he has 

 been blamed even by his own countrymen for want of precision 

 in this respect. The work of Lacepede, however, will always 

 retain its place as an extensive collection of useful and varied in- 

 formation on a very important and interesting class of animals. 



Blainville, in his Prodromus of a new distribution of the ani- 

 mal kingdom, arranges the Fishes into two subclasses, the Car- 

 tilaginous and Osseous, the first of which includes four orders, 

 and the second two tribes, three orders, and four sub-orders. 



The classification, however, now most generally adopted is 

 that given by Baron Cuvier in his Regne Animal ; and as this 

 is the arrangement meant to be followed in the following pages 

 it is necessary to give it in detail. The Class of Fishes, he ob- 

 serves, present many difficulties when an attempt is made to di- 

 vide them into orders established on fixed and precise characters ; 

 but the two great divisions, founded on the character of their 

 bones, as being Cartilaginous or Osseous, are natural andwellmark- 

 ed. The FIIIST SERIES or Chondropterygii have, as a general 

 character, the palatine bones arranged so as to supply the place 

 of those of the upper jaws. These he divides into three orders, viz. 



I. CYCLOSTOMI. Jaws fixed in an immoveable ring, and the 

 branchial openings numerous. 



II. SELACHII. With the branchiae as in the preceding order, 

 but not their jaws. * 



* In his Introductory observations on the characters of the class, Cuvier indicates 

 these two divisions as orders ; but in the after details he arranges them as two fatni- 



