ANNOTATED LIST OF THE SPECIES 139 
103. TYMPANOPLEURA NIGRICOLLIS Eigenmann and Allen, sp. nov. 
Plate V, figs. 2 and 3; plate VI, fig. 3 
15788, 1, male, type, 106 mm. to tip of upper caudal lobe, Iquitos, Allen, September, 1920. 
15788, 3, females, paratypes, 65-117 mm., Iquitos, Allen, September, 1920. 
15789, 1, female, paratype, 95 mm., Rio Ucayali near Orellana, Allen, August, 1920. 
Related to T. polystictus (Steindachner) and T. rondoni (Ribeiro), both of 
which are probably members of the genus T'ympanopleura rather than Ageneiosus. 
Head to end of bony opercle 3.2-3.5 in the length; depth 5.0-5.5; D. I, 6; 
A. 26-28; head wedge-shaped, slightly concave behind the eye; eye about 1.6 in 
the snout, about 4.5 in the head, about 3 in the width of the head, width of rictus 
about equal to snout and eye; length of gape about 8 in the width of the rictus: 
snout broad, semicircular; maxillary barbel of male osseous to beyond the rictus, 
equal to length of eye; the barbel fleshy in female; upper jaw slightly projecting 
all round; depth of premaxillary band of teeth about 4 of eye; profile but slightly 
concave; occipital process at its base about equal to its length. 
Pectoral not reaching to the ventral, the spine about equal to the snout and 
eye, the front of the spine roughened, with less than 20 serrae on the posterior 
face, largest at about the middle of the spine; dorsal spine similar, a little longer, 
the serrae not so high; caudal forked; anal low, not faleate; origin of anal about 
equidistant from base of middle caudal ray and pectoral spine; ventral reaching 
beyond origin of anal, less than pectoral spine. 
Lower surface of head between rami of the Jaws black; a dark area forward 
from pectoral, another forward from ventral; edge of lower jaw dark; side above 
anal dark; a light band from lower caudal lobe up and forward to the eye; upper 
part of head and back to caudal dark; a dark area along base of caudal; fins dusky, 
upper part of sides light, at times a dark streak along the lateral line. 
Air bladder very large, nearly as long as snout and eye, with two coeca longer 
than pupil. 
104. TYMPANOPLEURA ALTA Eigenmann and Myers 
s 
Plate VI, fig. 4 
Tympanopleura alta Eigenmann and Myers, in Myers, 1928, Ann. Mag. Nat. Hist., (10), IT, 85. 
15790, 1, 182 mm., type, Iquitos, Allen, September, 1920. 
15977, 1, 128 mm., paratype, Iquitos, Morris, 1922. 
Head 3.0-3.2; depth 44.5; D. I, 6; A. 32; eye 2.5-3 in the snout, 5.5-7 in the 
head, 3.5 in interorbital; barbel very small (female only) scarcely reaching to 
rictus; length of gape equals half the width between rictus and rictus; width of 
head less than width in front of pectorals; snout pointed, upper jaw projecting 
considerably beyond the lower jaw; depth of premaxillary band of teeth about 2 in 
eye; profile very concave (the concavity is a little greater than in drawing); fontanel 
reaching to near middle of eye; width of occipital process about equal to its length. 
Pectoral reaching beyond origin of ventral; pectoral spine a little longer than 
snout and eye, the outer edge rugose, the inner edge with numerous (over 30) 
