330 64 



Intestinal canal simple, without stomachal sac. Air-bladder present, ductless. 

 Ventrals (if present) abdominal in position, 5 — 7 rays. Fin-rays of pectoral, (se- 

 cond) dorsal and anal fins distally unbranched. 



A. Post-clavicle and metapterygoid present; anterior 4—6 vertebrae elongated, 

 more or les modified; vertebræ with articular processes. (4 — 5 branchi- 

 ostegal rays.) Lateral line canals present (at least on head: Cenlriscus): 

 Aulostomata ("Bouches-en-flùle"). 



1st Family: Centriscidœ. 



Mouth toothless. Body laterally compressed, stiff; tail short, movable. All 

 the components of mandibular suspensorium present; palatine, ento- and meta- 

 pterygoid connected with the elongated etlimo-vomerine part of skull. Nasal and 

 preorbital well developed, the first containing a lateral line canal. Hyoid of normal 

 composition; 4 branchiostegal rays; branchial skeleton complete, upper and lower 

 pharyngeals carrying teeth. Posttemporal suturally united to skull; supraclavicle 

 present; scapular foramen enclosed in scapula; pectoral pterygials stout, leaving 

 no interspaces. Anterior 5 — 6 vertebræ elongated, their transverse processes, except 

 those of the first and last, firmly connected with large dermal plates. Two dorsal 

 fins, anterior spinous, the spines, except 1 — 3 of the foremost, fused with their 

 interneurals; posterior dorsal opposite to anal. Outer ray of ventral spinous. Two 

 nasal openings. Appendices pyloricæ absent. 



Genera: Centriscus, Amphisile. 



2nd Family: Aulostomidœ. 



Moulh toothed; body elongated, tail short. Occipital condyle convex. Ecto- 

 pterygoid wanting, other suspensory bones present; palatine, ento- and metaptery- 

 goid (in Fistularia also symplectic) connected with ethmo-vomerine part of skull. 

 Nasal quite rudimentary or absent; preorbital rudimentary or absent. Hyoid com- 

 posed as usual of 5 pieces; 4 or 5 branchioslegals; branchial skeleton reduced, 

 only one basibranchial being ossified, 4th epibranchial absent, the remaining 3 

 more or less separated from their cerato-branchials; Isl pharyngobranchial absent, 

 2nd— 4th and lower pharyngeals provided with teeth, l^osttemporal present, supra- 

 clavicle present or absent ; scapular foramen enclosed in scapula ; pterygials elongated, 

 leaving interspaces between. Anterior 4 vertebræ much elongated and suturally 

 united, their transverse and spinous processes forming continuous lamellæ. Trans- 

 verse processes of free abdominal vertebræ divided into an anterior and a posterior 

 part. First dorsal fin, if present, spinous, second dorsal opposite to anal. Ventral 

 fin with 6 rays, the outer unbranched, but jointed. Lateral line canals developed. 

 Two nasal openings. One or two appendices pyloricæ. 



Genera: Aiilostoma, Fistularia. 



