156 PROCEEDINGS OF THE ACADEMY OP [1884. 



§ 2. Synopsis of Families. 



I. Dermal armature absent or developed only as plates on sides or 



back; vertebrae numerous (30 to 86) ; pubic bones connected 

 with scapular arch ; spinous dorsal represented by isolated 

 spines. 



1. Vertebrae anteriorly little enlarged ; ventrals subthoracic, 



with enlarged spines {G aster osteoidea). 



a. Branchiostegal rays three ; ventrals with one ray each ; 



snout conic or but slightly tubiform. Gasterosteidse. 



b. Branchiostegal rays four ; ventrals with four rays each ; 



snout tubiform. .... Aulorhynchidae. 



2. Vertebrae anteriorly (first four) elongate ; ventrals sub- 



abdominal or near middle, without spines, but with 6 (or 5) 

 rays (Aulostomoidea). 



c. Dorsal spines developed, weak ; body compressed, moder- 



ately long, with ctenoid scales. . . Aulostomidse. 



d. Dorsal spines undeveloped ; body depressed or sub- 



cylindrical, very long, without scales (caudal with the 

 two middle rays produced into a long filament). 



Fistulariidae. 



II. Dermal armature superficial, developed anteriorly and espe- 



cially about the back; four anterior vertebrae much elongate ; 

 tail with its axis continuous with that of the abdomen ; 

 branchihj^als and pharyngeals mostly present (fourth 

 superior branchihyal and first and fourth superior pharyn- 

 geals only wanting) ; pubic bones not connected with the 

 scapular arch; a spinous dorsal fin developed (Macrorham- 

 phosoidea). . . . . , Macrorhamphosidae. 



III. Dermal armature connate with the internal skeleton, and 



developed as (1) a dorsal cuirass in connection with the 

 neuropophyses and (2) lateral shields connected with the 

 ribs ; vertebrae reduced ; six or more anterior vertebrae 

 extremely elongate, with normal articulations of centra ; 

 tail with its axis deflected from that of the abdomen by 

 encroachment of a dorsal cuirass over the dorsal fin ; 

 branchial system feebly developed (fourth superior bran- 

 chihyal and all the superior pharyngeals wanting) ; pubic 

 bones not connected with the scapular arch ; a spinous 

 dorsal feebly developed under the posterior projection of 

 the dorsal buckler. (Amphisiloidea) . . Amphisilidee. 



