78 Fretp Museum or Naturat History — Zoétocy, Vor. X. 
Body elongate, the dorsal region elevated; profile slightly convex; 
mouth sub-inferior, 24 of band of premaxillary teeth exposed; band of 
teeth in lower jaw about % width of the premaxillary band; maxillary 
barbels reaching end of shortest caudal rays; eye 4.15 in head; snout 
2.30; interorbital 3.86; dorsal rather high, its spine 1.20 in head; first 
dorsal ray 1.04; last dorsal ray 2.82; longest dorsal ray not reaching 
adipose fin; depth at origin of adipose fin 2.04 in head; depth of caudal 
peduncle 5.50; base of adipose fin 1.41 in head; pectoral spine slightly 
roughened on outer margin, its inner margin with 24 rather strong 
retrorse teeth, its length 1.28 in head; humeral process scarcely reaching 
middle of pectoral spine, its length 2.47 in head; caudal fin deeply 
forked. pat 
Color light silvery below, darker above; sides and top of head with 
many small black spots. 
Tuyra River basin. 
lMegalonema robustum sp. nov. 
Type No. 7578, F. M. N. H.; length 290 mm.; Rio Tuyra, Marriganti, 
Panama. 
Head 3.8; depth 4.4; D. I, 6; A. tro. 
Body elongate, robust, profile nearly straight; dorsal region ele- 
vated; mouth sub-inferior, about half of band of premaxillary teeth 
exposed; band of teeth of lower jaw nearly as wide as premaxillary band; 
maxillary barbels reaching to or slightly past middle of adipose fin; eye 
5.0 to 5.6 in head; snout 2.3; interorbital 3.0 to 3.4; dorsal fin rather 
high, its spine 1.1 to 1.2 in head; first dorsal ray .9 to 1.1; last dorsal ray 
2.8; longest dorsal ray not reaching adipose fin; base of adipose fin 1.2 
in head; depth at origin of adipose fin 1.5 in head; depth of caudal 
peduncle 3.1 to 3.2; pectoral spine roughened on outer margin, the 
inner with 32 rather small retrorse teeth, its length 1.1 in head; humeral 
process 2.3 in head, not reaching middle of pectoral spine. 
Color dark olivaceous above, silvery below; sides and head without 
spots. 
Tuyra River basin. 
Family PYGIDIIDZ. 
Pygidium striatum sp. nov. 
Type No. 7579, F. M. N. H.; length 84 mm.; Rio Cana, Cana, 
Panama. 
Head 5.3 to 6.3; depth 7.4 to 8.2; D. 8; A. 6. 
