376 FISHES. 



and though in his arrangement they of course form but one 

 order, yet these families are so well distinguished that no in- 

 convenience can arise from this circumstance. 



IX. ACA^THOPTEKYGII. First portion of the dorsal fin, 

 or first dorsal fin where there are two, with spinous rays. This 

 very numerous order is divided into seven families, 1. Tcenioi- 

 des ; 2. GoUoides ; 3. Labroides ; 4. Percoides ; 5. Scombe- 

 roides ; 6. Squamipennes ; 7. Fistularidce. The arrangement 

 in a tabular form will stand thus : 



SUB-CLASS I. CARTILAGINOUS FISHES. 



ORDER I. CYCLOSTOMI, 



II. PLAGIOSTOMI, (SELACHII, Cuv.) 

 III. STURIONES. 



SUB-CLASS II. OSSEOUS FISHES. 



ORDER IV. PLECTOGNATHI, 

 V. LOPHOBRANCHII, 

 VI. MALACOPTERYGII ABDOMINALES, 

 VII. MALACOPTERYGII SUJBRACHIATI, 

 VIII. MALACOPTERYGII APODES, 

 IX. ACANTHOPTERYGII. 



In addition to the systematic writers on Ichthyology now 

 mentioned, many others might be noticed, whose labours in de- 

 lineating and describing portions of this important class of ani- 

 mals have been useful to science. A list of the chief of these 

 will be found at the end of this volume. Pennant in his British 

 Zoology, Montague and Donovan, the last of whom particu- 

 larly in his extensive works on British Zoology, have done much 

 towards the investigation of indigenous species ; and Baron 

 Cuvier's extensive and important work on fishes, now in pro- 

 gress, which is intended to include the whole discovered species, 

 will, it is probable, leave little to be desired regarding our know- 

 ledge of this class. The portion of Dr Shawls General Zoolo- 

 gy on fishes may be referred to for good figures of many spe- 

 cies, though most of them are copied from previous writers. 



The form of fishes seems as admirably adapted for motion in 

 water as that of birds for flight in the air. Suspended in a li- 

 quid of nearly the same specific gravity as their own bodies. 



