NATURAL SCIENCES OP PHILADELPHIA. 27 1 



in eleven rows on each side. The lateral line runs through twelve on the 

 sides of the back, is then deflected through three, and thence runs along the 

 fifth row from the back through thirty-six. 



D. 36. A. 2, 36. C. I. 1, 8, 1, I. 



The color is a light yellowish brown, rendered darker on the back by con- 

 gregations of dark dots on the scales. There is a margaritaceous spot behind 

 and beneath the eye, and the operculum is also colored in the same manner. 



Total length, 2-3 100 



Greatest height 9 



Height behind dorsal fin 3 



Thickness of pectorals 6 



Head Length from lower jaw to bony operculum 17 



" from upper jaw 16 



Height at preoperculum 9 



" behind eyes 6 



Thickness at preoperculum 7 



" behind eyes 4 



Eye Diameter 4 



Distance from snout 3 



Dorsal Distance from snout 25 



Anal Distance from snout 23 



Caudal Length 12 



Pectoral Length 21 



Ventral Length 7 



This species is a native of the waters of Lower California. Several speci- 

 mens were obtained by Mr. John Xantus at Cape St. Lucas, and are now pre- 

 served in the Museum of the Smithsonian Institution. * 



Synopsis of the POLYNEMATOIDS. 



BY THEODORE GILL. 



The family of Polynematoids has been recently established as now accepted, 

 and its limits very accurately defined by Dr. Glinther in his catalogue of the Ac- 

 anthopterygian fishes of the British Museum. The principal characteristics by 

 which its representatives can be at once recognized are the free filaments on 

 each side of the breast below the pectorals, the protuberant snout, distant 

 dorsal fins, and the abdominal position of the ventrals. The family charac- 

 ters in detail are the following : 



Family POLYNEMATOIDS Bleeker. 



Polynematoidae Giinther, Catalogue of the Acanthopterygian Fishes, &c.,vol. ii. 

 Polynemidse partim Richardson, &c. 

 Percidae pt. Cuvier, &c. 



Body oblong or moderately elongated and highest over the anus, which is 

 subcentral. Caudal peduncle oblong and robust. Scales regularly imbricated, 

 generally ctenoid and muricated, and of moderate or rather small size, ex- 

 tending on the head and fins. 



Lateral line continous and nearly straight. Continued on the caudal fin. 

 Head oblong, moderate or rather small, compressed and slowly decreasing 

 in size towards the snout, which is high and protuberant. Eyes moderate or 

 large, and wholly or mostly anterior. Nostrils double. Suborbital bones very 

 low ; none articulated with the preoperculum. Opercular bones normally 

 developed. Suboperculum oblique and forming the posterior angle. Mouth 

 moderately oblique, and continued under the eyes behind. Teeth acute, 

 always present on the jaws, and generally on the palate. Branchiostegal 



1861.] 



