166 Annals of the Carnegie Museum. 



with a single series of five or six incisors, maxillary with three similar, 

 but smaller, teeth. The incisors of both upper and lower jaws with a 

 broad, sometimes nicked, central lobe, and a much smaller point on 

 each side, the cutting edges forming a continuous curve. Caudal 

 naked; lateral line complete; cheeks not entirely covered by the 

 suborbitals. 



This genus bears a close resemblance to Henochilus. I am not sure 

 whether it is derived from Henochilus and has lost its inner premaxil- 

 lary teeth, or whether Henochilus is in process of developing them. 



2. Psalidodon gymnodontus sp. no v. 

 Plate IV, figs. 2-3. 



Type. — One specimen, 189 mm. C. M. No. 3204. Porto Uniao, Rio Iguassu. 

 Dec. 27, 1908. 



Cotypes. — Two specimens, 145 and 165 mm. C. M. No. 3205. Same place 

 and date. 



Head 4.25; depth 3.5 in the type, 2.8 in the specimen 145 mm. 

 long; D. 11; A. 21; scales 6-36 to 39-4 or 5; eye equal to the snout, 

 3.5-3.75 in the length of the head; interorbital 3 or a little less; 

 maxillary-premaxillary border 2.5 in the head. General shape vary- 

 ing greatly, elongate to deep, compressed. Ventral surface rounded, 

 without median series of scales; predorsal area narrowly rounded, 

 without regular median series of scales; about twelve series of scales 

 in front of the dorsal. Occipital process a little less than 6 in the dis- 

 tance from the base to the dorsal, bordered by three scales on the 

 side; head convex and smooth; fontanels narrow, the anterior about 

 half as long as the posterior with the occipital groove; second sub- 

 orbital leaving a naked area a little more than a fourth of its 

 own width around its entire margin. Gill-rakers 5 + 13, slender and 

 pointed, about two-fifths orbital diameter in length. Origin of dorsal 

 about an orbital diameter nearer the snout than to the base of the 

 middle caudal rays, its margin truncate, its first ray 5 or 6 in the 

 length; caudal forked, its lobes 4-4.5 in the length; anal distinctly 

 emarginate, its anterior rays 6-7.5 in the length; first anal ray nearly 

 an orbital diameter behind the vertical from the last dorsal ray; ven- 

 trals reaching to anus, 7 in the length; pectorals not nearly reaching 

 ventrals. Lateral line complete, somewhat decurved to above the 

 end of the pectoral; scales regularly imbricate except over the anal, 

 each with numerous divergent radial striar, caudal naked; anal with 



