SOUTH AMERICAN NEMATOGNATHI. 161 



We have examined two specimens from the Obispo 

 River, Panama, .146 m. and .12 m. They were col- 

 lected by Dr. Steindachner, Hassler Expedition, in 1872, 

 and are probably two of the four type specimens. 



Body elongate, slender, much compressed posteriorly; 

 greatest width of head about 1| in its length, its depth 

 at base of occipital process 1J; width of snout at the 

 rictus about 2J. Profile curving very gently from origin 

 of the dorsal fin to the posterior nostrils, thence ab- 

 ruptly decurved. The fontanel forms a depression be- 

 tween the eyes, otherwise the interorbital is flat; post- 

 orbital convex transversely. 



Teeth in bands of about equal width in both jaws, in- 

 terrupted in the middle in the lower jaw, the width of 

 the intermaxillary band 3f in the head. 



Occipital process reaching quite to the dorsal plate, 

 articulating with it, the process notched at its tip to re- 

 ceive the dorsal plate. 



Eye 1-f-lf in snout, 3-f in head, the interorbital about 

 one-sixth less than the diameter of the eye. 



Maxillary barbels extending to origin of adipose fin 

 and tips of ventrals, mental about to base of pectoral, 

 and postmental barbels to middle of pectoral ffn. 



Gill-membranes meeting under anterior portion of 

 eye. Humeral process about to middle of pectoral spine. 



Dorsal spine inserted nearer the tip of the snout than 

 to the origin of the anal fin; straight, scarcely roughened 

 in front except near the tip where there are several 

 notches, its posterior margin with very short teeth along 

 the basal portion in the larger perfectly smooth in the 

 smaller specimen, with short notches near the tip in 

 both; dorsal spine IJ-lg in head, the first ray very nearly 

 as high as length of head, the base of the fin less than 

 its height. 



Adipose fin 3J-3f in the length; in the larger 

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