436 TELEOSTEI. ACANTHOPTEttYGII. 



Twelfth group. GASTEROSTEIFOKMES. 



The spinous dorsal, when present, short or formed of isolated spines ; 

 veutrals abdominal, sometimes imperfectly developed. 



XXXVII. Anterior bones of the head forming a 

 tube having a small mouth at its extremity. 



Ventrals with 6 rays Aulostomateidae. 



XXX VI II. Anterior bones of the head forming 

 a tube having a small mouth at its extremity. 



Ventrals imperfectly developed CentriscicUe. 



Thirteenth group. CHAN1STFORMES. 



Body elongate. No labyrinthiform superbranchial organ, but a pro- 

 minence on the epitympanic bone. Dorsal and anal fins long, all destitute 

 of spines. 

 XXXIX Ophiocephalidae. 



Fourteenth group. LABYRINTHIBRANCHIL 



Body compressed, oblong or elevated. A labyrinthiform superbranchial 

 organ arising from the branchial arches, and employed for respiratory 

 purposes. 

 XL Labyrinthici. 



Fifteenth group. TRACK YPTERIFORMES. 



Body elongate and strongly compressed. Skeleton soft. Dentition 

 feeble. Anal fin absent ; caudal not in the longitudinal axis of the fish 

 or else rudimentary ; ventrals thoracic. 

 XLI Trachypteridae. 



Sixteenth group. LABRIFOEMES. 



The lower pharyngeal bones coalesced along the median line, and with 

 or without a median longitudinal suture. A single dorsal fin, the number 

 of spines and rays being nearly equal j soft anal similar to the soft dorsal ; 

 ventrals 1/5, thoracic. 



XLII. Pseudobranchise present ; scales ctenoid . . Glyphidodontidae. 

 XLIII. Pseudobranchise present ; scales cycloid .. Labridae. 

 XLIV. Pseudobranchiae absent . . . Chromides. 



Family I. PERCIME. 



Pseudobranchiae present. Body generally oblong, never elon- 

 gate. Muciferous system of head rudimentary, or but slightly 

 developed. Eyes lateral. No superbranchial organ. Preopercle 

 entire or serrated ; cheeks not cuirassed. Mouth moderately or 





