ANNOTATED LIST OF THE SPECIES 105 
Head 5; depth 5.9; D. 1, 6; A. 10; eye 4; interorbital 3.5; width of the head 1.45 
in its length, moderately convex above; occipital bone with lines radiating anteriorly 
and posteriorly from the fontanel; occipital fontanel + the length of the eye and 4 
as wide as long; the top of the head covered with thin skin; frontal fontanel not 
quite extending to above the posterior margin of the pupil; eye elliptical, its length 
only slightly less than the interorbital space; mouth inferior, small; no teeth on the 
intermaxillary; the lower jaw with a band of fine teeth set in a fleshy cushion; gill 
membranes separate to below the anterior margin of the eye; gill rakers slender, 
simple, } the length of the gill filament, 8 + 16; maxillary barbels slightly com- 
pressed, extending more than the length of the head beyond the end of the middle 
caudal rays; outer mental barbels reaching considerably beyond the base of the 
ventrals, inner mentals beyond the middle of the pectorals; the pectoral and dorsal 
spines weak, all broken and the tips missing; the basal portion of the posterior 
margin of the pectoral spine with several weak thorns, the anterior margin slightly 
roughened; second dorsal ray extending considerably beyond the origin of the adi- 
pose when depressed; first soft rays of the pectorals not near reaching base of ven- 
trals; ventrals not reaching anal by a distance equal to one half their length; anal 
slightly emarginate; distance of the origin of the dorsal from the tip of the snout 3 
times in the total length; adipose fin separated from the dorsal by a distance equal 
to 2? the base of the dorsal, its length 2.9 in the total length; caudal lobes broken 
and missing. 
Iridescent; a dark spot Just in front of the origin of the dorsal; dorsal fin with 
chromatophores on the interradial membrane. 
47. PIMELODUS JIVARO Higenmann and Pearson, sp. nov. 
Plate IV, fig. 2 
15859, 3, cotypes, 105 mm., Creek, Rio Morona, Allen, October, 1920. 
15813, a, 2, 85 and 98 mm., Creek, Rio Morona, Allen, October, 1920. 
Close to P. clarias, from which it differs by possessing a shorter head, a higher 
dorsal fin, a longer adipose, and caudal peduncle less deep. 
Head 4.2; depth 4.75; D. I, 6; A. 12; eye 4; interorbital 3.8 to 4; width of the 
head 1.5 in its length, convex above, the surface of the bones granulate; frontal 
fontanel ending above the posterior edge of the pupil; occipital fontanel remaining 
as an oval depression; eye elliptical, its length equal to the interorbital width; mouth 
inferior; most of the band of the intermaxillary teeth exposed, the depth 7 times in 
the width; no teeth on vomer; gill rakers slender, simple, one half the length of the 
gill filament, 4-12; maxillary barbels compressed, their length 13 times the total 
length or slightly greater, outer mentals reaching to the origin of the anal, the 
inner mentals to the middle of the pectoral spine; pectoral spine 4 the length of the 
head, the posterior margin in the larger specimen has 20 strong, pointed, recurved 
teeth, the anterior edge with as many smaller teeth; the longest ray of the pectoral 
almost reaching the base of the ventral; ventrals almost to anal; the anal high, 
emarginate, the highest ray almost twice as long as the anal base; distance of the 
origin of the dorsal from the tip of the snout 24 times in the total length; dorsal 
