Jordan and Rvermann. Fishes of North America. 827 



Remotely allied to the Perccsocex but showing also certain Percoid char- 

 acters is the singular 



Suborder RHEGNOPTERI. 



Actinosts of pectoral fin of 3 forms, 2 of them normal, supporting the 

 pectoral fin, 1 of them longitudinal, without rays, and the fourth a plate 

 on the coracoid, supporting 3 to 10 free and separate rays or feelers. Post- 

 temporal and shoulder girdle normal ; vertebra? 10 -f- 14 24 ; 2 separate 

 dorsal fins, the first of a few spines. Pseudobrauchise concealed ; ventrals 

 subabdorninal, behind pectorals. One family, Polynemidce, of uncertain 

 origin and affinities, (prjyvuu, to break asunder; irrspov, fin.) 



Family CIX. POLYNEMID.E.* 

 (THE THREADFINS.) 



Body oblong, compressed, and covered with rather large, loosely inserted, 

 ctenoid scales. Lateral line continuous, continued on the tail, usually 

 forked, with a branch on each lobe. Head entirely scaly ; snout more or 

 less conical, projecting over the mouth, which is rather large, inferior, with 

 lateral cleft ; premaxillary protractile, its basal process vertical ; maxil- 

 lary without supplemental bone, extending much beyond the eye, which 

 is anterior, lateral, rather large, with a well-developed, adipose eyelid. 

 Villiform teeth on jaws, palatines, and sometimes on vomer. Pseudo- 

 branchiae concealed. Branchiostegals 7. Gill membranes separate and 

 free from the isthmus. Gills 4, a slit behind the fourth. Two separate 

 dorsals, somewhat remote from each other, the first of 8 feeble but rather 

 high spines, the first and last spines very short, the third longest; the 

 second dorsal equal to first in height but base somewhat longer, of soft 

 rays only. Anal fin either similar to or much longer than soft dorsal ; caudal 

 fin rather long, widely forked. Second dorsal, anal, and caudal fins more 

 or less covered with small scales ; the first 3 or 4 dorsal spines winged. 

 Ventrals I, 5, abdominal, but not far removed from pectorals; pectoral fins 

 moderate, placed low, in two parts, the lower and anterior portion of sev- 

 eral filiform articulated appendages, free from each other, used as organs 

 of touch. In the young the dorsal, caudal, and pectoral fins are dusky, 

 the anal and ventral fins white ; all the fins grow darker with age, the 

 pectorals usually becoming black, the operculum blackish. Bones of the 

 skull with a well-developed rnuciferous system as in Sciamida-. Basis cranii 

 double, with muscular tube; post-temporal bifurcate; hypercoracoid 

 with median foramen ; superior pharyngeal bones 4. Pectoral actinosts 

 divided ; 2 of them normal, supporting the pectoral fin, 1 longitudinal, 

 without rays, and 1 a plate on the coracoid, supporting the pectoral fila- 

 ments. Stomach ca'cal, with a few pyloric appendages. Air bladder 

 various, sometimes wanting. Vertebra? 10 + 14 = 24. Genera 4, Galeoides, 



For a review of this family see Kirsch, Annals N. Y. Ac. Sci., v, April, 1890, 231-236. 



