320 Annals of the Carnegie Museum. 



A. .5; twenty-five to twenty-seven lateral scutes; five scutes between 

 the supra-occipital and the dorsal plate, color light brown, with a few 

 indistinct spots on the fins and a faint band back of the eyes. 



This species is easily recognized by the expanded snout and many 

 delicate keel-like ridges on the scutes. 



All the specimens were collected in a grassy, cool, shady, swampy 

 creek known as Igarape de Cachoeira Grande, near Manaos, November 

 30, 1909. 



Platysilurus, gen. nov. 



Teeth all alike, and those on the vomer in two patches; upper 

 jaw slightly longer, head more or less conical, not greatly depressed; 

 fontanel continued behind the eyes as a deep groove, which is con- 

 tinued into the dorsal plate, which is firmly joined to the occipital 

 process; snout rather long and somewhat pointed; head almost twice 

 as long as broad; caudal deeply forked, the lower lobe broader and 

 longer; a bony process back of upper angle of gill-opening ending in 

 a few roughened plates on the anterior part of the lateral line. 



The single species of this genus resembles Platy stomatichthy s stiirio 

 in nearly all details, excepting the stronger dorsal and pectoral spines, 

 the much shorter and less pointed snout, and the larger eyes. 



Platysilurus barbatus, sp. nov. 



Type. — No. 2987. 17.5 cm. Sao Antonio de Rio Madeira, 

 Nov. 3, 1909. 



Cotypes. — Nos. 2988 a-c. 9.5-12.5 cm. Rio Machupo, near San 

 Joaquin, Bolivia, September 6, 1909. 



D. .6; A. II; P. -9; head 3.33; depth at origin of dorsal 6; first 

 rays of anal three times as long as the last; adipose of greater extent 

 than the anal, and about equal to the distance between it and the 

 last dorsal ray, two and a half times as long as high; caudal peduncle 

 short and almost round; pectoral spine longer than the dorsal, three- 

 fourths as long as the head and denticulated on both margins; dorsal 

 spine denticulated on the posterior margin; eye 6 in head, about 3 

 in the snout, 1.25 in the interorbital space; humeral process rather 

 short and spine-like; maxillary barbel three times as long as the body, 

 its proximal part wire-like; post-mentals extend to middle of pectoral; 

 lower caudal lobe fully one-third as long as the body; head broader 

 than deep; snout tapered and sub-conical; top of head bony and 



