DEC. 28, 1916. FISHES OF PANAMA MEEK AND HILDEBRAND. 299 



Closely related to B. oligolepis Regan (Ann. & Mag. Nat. Hist., Ser. 

 8, IX, 1913, 462). We have not seen the type of the latter, but have 

 for comparison specimens from the type locality (Rio Condoto), identi- 

 fied by Dr. Eigenmann. The differences noted are: a. The more 

 strongly projecting upper jaw of the latter, exposing 2 series of pre- 

 maxillary teeth, while in the former the upper jaw projects but little 

 and the second series of teeth is well covered by the lower lip. b. The 

 last series of premaxillary teeth is situated well in front of the teeth in 

 lower jaw, leaving a space between them when the mouth is closed. 

 In B. argenteus the last series of premaxillary teeth are close in front of 

 the teeth in lower jaw, touching the latter when the mouth is closed. 



Habitat: Pacific slope of Panama. 



30. Genus Piabucina Cuvier & Valenciennes. 



Piabucina Cuvier & Valenciennes, Hist. Nat. Poiss., XXII, 1849, 161 

 (type Piabucina erythrinoides Cuvier & Valenciennes). 

 Body oblong, covered with large scales; ventral region rounded; 

 mouth moderate; teeth in upper jaw in one series, tricuspid, those of 

 lower jaw in two series; maxillary with few teeth; nostrils close together; 

 gill-openings wide, the membranes not attached to the isthmus; lateral 

 line wanting; dorsal and anal fins short; dorsal fin inserted behind ventrals. 

 Neither of the two species listed below grows large. Our largest 

 specimens are only a little over 200 mm. in length. 



KEY TO THE SPECIES. 



a. A dark lateral band extending from above posterior angle of 

 opercle to base of caudal and situated on median line of side, 

 this band broad at shoulder, becoming narrower, posteriorly 

 often broken up into blotches, ending in a large caudal spot; 

 body slender, the depth 4 to 4.6 in length; depth of caudal 

 peduncle 2.16 to 2.7 in head; maxillary reaching middle of eye; 

 origin of dorsal midway between margin of preopercle and tip 

 of adipose. panamensis, p. 300. 



aa. A dark lateral band extending from posterior angle of opercle to base 

 of caudal, situated notably below median line of side, anteriorly 

 very obscure and not connected with the shoulder spot, becoming 

 more distinct above ventrals, not broken up into spots posteriorly; 

 no caudal spot; body rather robust, the depth 3.6 to 3.95 in length; 

 depth of caudal peduncle 1.75 to 2 in head; maxillary reaching 

 slightly past anterior margin of eye; origin of dorsal midway be- 

 tween tip of adipose and margin of opercle. festa, p. 301. 



