204 ZOOLOGY. 



Order III. Phaeyngognathi. 



Internal skeleton ossified. Scales sometimes cycloid, sometimes ctenoid. 

 Inferior pharyngeal bones coalesced. Air-bladder without a duct in the 

 adult. 



Sub-order 1. Malacopterygii. 

 ScomberesocidaB. 



Sub-order 2. Acanthopterygh. 

 Chromidae. Cyclo-Labridae. Cteno-Labridae. 



Order IV. Anacanthini. 



Internal skeleton ossified. Scales sometimes cycloid, sometimes ctenoid. 

 Fins sustained by flexible or jointed rays. A^entrals beneath the pectorals 

 or entirely absent. Swimming bladder without air-duct. 



Sub-order 1. Apodes. 

 Ophididae. 



Sub-order 2. Thoracici. 

 Gadidae. Pleuronectidae. Echineidse. 



Order V. Acanthopteri. 



Internal skeleton ossified. Scales ctenoid. Fins with one or more 

 ot" the anterior rays unjointed or inflexible. Ventrals generally beneath or 

 anterior to the pectorals. Swimming bladder without duct. 



Percidae. Atherinidae. Theutyidae. 



Sclerogenidae. Mugilidae. Fistularidae. 



Sciaenidae. Notacanthidae. ■ Gobiidae. 



Labyrinthi-branchii. Scomberidae. Blenniidae. 



Sparidae. Squamipennes. Lophiidae. 



Maenidae. Taenioidei. 



Order VI. Plectognathi. 



Internal skeleton only partly ossified. Scales ganoid or spinous. Max- 

 illaries and intermaxillaries firmly nnited. Swimming bladder without air- 

 duct. 



Balistidae. OstracionidaB. Gymnodontidae. 



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