4 TELEOSTEI. 



Eleventh group — Mugiliformes. 



Two distinct dorsal fins, the anterior short, or similar to the posterior : ventrals well developed, abdo- 

 minal, 1/5. Vent remote from the end of the tail and posterior to the ventral fins. 



30. Sphyrceniclce. Body elongate, sub-cylindrical. Teeth large and cutting. Vertebras 24. 



31. Aiherinidce. Body more or less elongated, and somewhat sub-cylindrical. Dentition feeble, or 

 moderate. Vertebras usually exceeding 10/14. 



32. Mugilidce. Body more or less elongated, and somewhat sub-cylindrical. Dentition feeble. First 

 dorsal fin consisting of four stiff spines. Vertebras 24. 



Twelfth group — Gasterosteiformes. 



The spinous dorsal, when present, short or formed of isolated spines : ventrals abdominal* sometimes 

 imperfectly developed. Vent remote from the end of the tail, and posterior to the ventral fins, when they are 

 present. 



33. Aulostomateidce. Anterior bones of the head forming a tube having a small mouth at its extremity. 

 Ventral fins with six rays. 



34. Centriscidce. Anterior bones of the head forming a tube having a small mouth at its extremity. 

 Two dorsal fins, the first short, the soft and the anal of moderate extent : ventrals imperfectly developed. 



Thirteenth group — Channiformes. 



Body elongate. No labyrinthiform superbranchial organ, but a bony prominence on the epitympanic 

 bone. Dorsal and anal fins long, all destitute of spines. Vent remote from the end of the tail, and posterior 

 to the ventral fins, when such are present. 



35. Ophiocephalidce. Ventral fins present, or absent. 



Fourteenth group — Labyrinthibranchii. 



Body compressed, oblong or elevated. A labyrinthiform superbranchial organ arising from the bran- 

 chial arches, and employed for respiratory purposes. Vent remote from the end of the tail, and posterior to 

 the ventral fins. 



36. Labyrinthici. Dorsal and anal spines present, and often numerous. 



Fifteenth group — Trachypteriformes. 



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. 



37. Trachypteridce as defined for the group. 



Sixteenth group — Labriformes. 

 Body oblong, elongated, or elevated and compressed. 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 : soft anal similar to the soft dorsal : ventrals 1/5, thoracic. 



38. Pomacentridce. Bones of the head may be armed, or smooth. Scales ctenoid. 



39. Ldbridce. Scales cycloid. 



* Dr. Giintber observes that in the Aulostomatei/los " the ventrals have an abdominal position in consequence of the prolongation 

 of the pubic bones, which are attached to the humeral arch." In the Centriscidce, on the contrary, we find the "ventral fins truly 

 abdominal, imperfectly developed." 



