98 



SUB-CLASSES AND ORDERS. 



Sub-class T. '^tltOSttU 



Fishes witli a bony skeleton and completely separated 

 vertebrae ; the posterior extremity of the vertebral column 

 either long or covered with bony plates. Bulb of the aorta 

 simple, with two opposite valves at the origin j branchial free. 



Order I. Acanthopterygil (Type^ Trumpeter.) 



Some of the rays of the dorsal, anal, and ventral fins not 

 articulated, forming spines ; the inferior pharyngeal bones 

 separated. Air-bladder, if present, without pneumatic 

 duct. (FamiHes 1 to 22.) 



Order II. Acanthopterygii Phaiyngognathi. (Type^ Parrot 



Fish.) 

 The inferior pharyngeal bones are coalesced, with or without 

 a medium longitudinal suture. Part of the rays of the 

 dorsal, anal, and ventral fins not articulated, forming 

 spines. (Family 23.) 



Order III. Anacanthini. f7>j9^, Flounder and Sole.) 



Vertical and ventral fins (except in Gadopsis) without 

 spinous rays. The ventral fins, if present, are jugular or 

 thoracic. Air-bladder, if present, without pneumatic duct. 

 (Families 24 to 28.) 



Order IV. Physostomi. (Type^ Salmon and Herring.) 



All the fin rays articulated : only the first of the dorsal 

 and pectoral fins is sometimes more or less ossified. The 

 ventral fins, if present, are abdominal, without spine. Air- 

 bladder, if present, with a pneumatic duct. (Families 

 29 to 38). 



Order V. Lopliohranclm. (Type^ Sea-horse.) 



The gills are not laminated, but composed of rounded lobes, 

 attached to tlie branchial arches. Gill-cover reduced to a 

 large simple plate. Air-bladder simple, without pneumatic 

 duct. A dermal skeleton. (Families 39 and 40.) 



Order VI. PlectognatJu. (Type^ Leather-jacket : Toad-fish.) 

 Teleosteous fishes, with rough scales, or with ossifications of 

 the cutis in the form of scutes or spines; skin sometimes 

 entirely naked. Skeleton incompletely ossified, with the 

 vertebrae in small number. Gills pectinate ; a narrow gill- 

 opening in front of the pectoral fins. Mouth narrow ; the 

 bones of the upper jaw generally firmly united. A soft 

 dorsal fin, belonging to the caudal portion of the vertical 

 column, opposite to the anal : sometimes elements of a 

 spinous dorsal besides. Ventral fins none, or reduced to 

 spines. Air-bladder without pneumatic duct. Nearly 

 all are marine fishes. (Families 41 and 42.) ^ . 



