438 FISHES. 



were inhabitants of considerable depths of the ocean. Both 

 the jaws of Pala-orhynchus are prolonged into a beak, whilst 

 in HemirhyncJms the upper exceeds the lower in length. 



Eighth Division — Acanthopterygii Cotto-scombpjformes. 



Spines develo'j^ed in one of the fins at least. Dorsal fins 

 either eontinuo us or close together; the sjnnoiis dorsal, if 2^'>^c- 

 sent, ahoays short ; sometimes modified into tentacles, or into 

 a suctorial dish ; soft dorsal always long, if the spinous is 

 ahsent ; anal similarly develojycd as the soft dorsal, and both 

 genercdly much longer than the spinous, sometimes terminating 

 in finlets. Ventral s, thoracic or jugidar, if ^^7Y.scn^, never 

 modified into an adhesive apparatus. No j^'^'ominent anal 

 papilla. 



Marine fishes, with few exceptions. 



First rA:\iiLY — Agronuridjs:. 



Body compressed, oblong or elevated, covered vnth minute 

 scales. Tail genercdly armed with one or more bony jAates or 

 sp)ines, tuhich are develop)ed with age, but ahsent in very young 

 individiials. Eye lateral, of moderate size. 3fouth small ; a 

 single series of more or less compressed, sometimes dcnticidated, 

 sometimes pointed incisors in each jaw ; 'palate toothless. One 

 dorsal fin, the spinous p)ortion being less developed than the soft ; 

 anal with tiro or tliree spines; ventrcd fins thoracic. Air- 

 bladder foi'lxd posteriorly. Intestines with more or less 

 numero2is circumvolutions. Nine abdomincd, and. thirteen 

 caudal vertebrcc. 



Inhabitants of the tropical seas, and most abundant on 

 coral-reefs. They feed either on vegetable substances or on 

 the superficial animal matter of corals. 



Extinct species of Acanthurus and Naseus have been dis- 

 covered in the Monte Bolca formation. 



I 



