276 Field Museum of Natural History — ZoOlogy, Vol. X. 



2.3 to 2.9; mouth small; jaws subequal; maxillary reaching anterior 

 margin of eye; premaxillary teeth usually 10 in number, each with 

 about 6 cusps, the middle ones slightly larger than the outer ones, 

 making the margins round; maxillary with 2 or 3 teeth similar 

 to those of premaxillary; teeth in lower jaw usually 12 in number, 

 close together, the expanded tips slightly overlapping, each with 

 about 6 cusps of nearly equal size, their margins straight, trans- 

 verse; lateral line incomplete, present on from 8 to 12 scales (present 

 on 20 scales in one specimen); scales thin, striate, 10 to 12 in ad- 

 vance of dorsal, 9 or 10 rows between dorsal and adipose; dorsal 



FlQ. 3. FRONT TEETH OF Pseudocheirodon affinis gea. et sp. aov. (After Cheirodon insignis 



(non Steindachner) Evermann & Goldsborough.) 



fin pointed, the anterior rays the longest, its origin midway between 

 tip of snout and base of caudal; adipose fin over last rays of anal, 

 notably nearer base of caudal than dorsal; caudal fin forked, the 

 lower lobe the longer; origin of anal under last rays of dorsal, its base 

 not quite equal to depth of body; ventral fins inserted slightly in 

 advance of dorsal, reaching nearly or quite to origin of anal; pectoral 

 fins somewhat longer than ventrals, usually not quite reaching base 

 of the latter. 



Color plain silvery, with a faint pltmibeous lateral band; a very 

 conspicuous, black, oval caudal spot, not extended on rays of caudal fin. 

 Head and body, except chest and abdomen, with dusky punctulations. 

 These largest above base of anal. Fins with dusky points, most 

 numerous on the anal fin, occupying principally the interradial 

 membranes. 



Numerous specimens were preserved. They range in length from 

 35 to 55 mm. Common but not abundant on both slopes of Panama. 

 We have designated as the type a male specimen, 38 mm. in length, 

 taken in the Rio Gatun, Monte Liria, Canal Zone. 



Habitat : Both slopes of Panama. 



