MALACOPTERYGII ABDOMINALES. 209 



cilia, interopercula, pterygoidals and tympanals, and at the extremity of which 

 is the mouth, composed as usual of the intermaxillaries, maxillaries, and the 

 palatine and mandibulary bones. 



Some of them, as the Fistulariae, have a cylindrical body, in others, as in 

 the Centrisci, it is oval and compressed. 



FISTULARIA, Linnaus. 



The name of these fishes, in particular, is derived from the tube common to 

 the whole family. The jaws are, at their extremity, slightly cleft in a nearly 

 horizontal direction. The head, thus elongated, constitutes a third or fourth 

 of the total length of the body, which is itself long and thin. There are six 

 or seven rays in the branchiae, and some bony appendages extend behind the 

 head, upon the anterior part of the body, which they strengthen more or less. 

 The dorsal is opposite to the anal fin. 



CENTRISCUS, Linnceus. 



In addition to the tubular snout of the family, the fishes of this genus have 

 an oval or oblong (not elongated) body, compressed on the side, and trenchant 

 beneath ; branchiae composed of but two or three slender rays ; a first spinal 

 dorsal and small ventrals behind the pectorals. The mouth is very small, and 

 cleft obliquely. 



ORDER II.. 

 MALACOPTERYGII ABDOMINALES*. 



THE second division of common fishes, or that of the Malacopterygii, 



contains three orders, characterised 

 by. the position of the ventrals or by 

 their absence. 



In this order the ventrals are sus- 

 pended to the under part of the abdo- 

 men and behind the pectorals, without 

 being attached to the bones of the 

 shoulder. It is the most numerous 

 of the three, and comprehends most of the fresh-water fishes, they are formed 

 to swim in more shallow water than those fishes which have the fins in a more 

 forward position. The abdominal fins also appear to keep the body more 

 steady in troubled waters than those that have them anterior to the pectorals. 

 We subdivide it into five families. 



Malacopterygii, soft-finned. 

 P 



