ANNOTATED LIST OF THE SPECIES 283 
Surinam to Rio de Janeiro and Peruvian Amazon 
———., 6, 68-93 mm., creek, Yurimaguas, Allen, November, 1920. 
, 2, 161-163 mm., brook, Iga, R. Itaya, Iquitos, Allen, September, 1920. 
Neoceratodus-like, short, broad-tailed, peduncle erect and compressed, basis 
of caudal and anal well built up and encased in a scaly armor, the former 5-6 
irregular rows. These specimens are lightest in color on the lower trunk region and 
caudal peduncle, from the base of the ventral fins caudally. 
The Erythrininae are given credit by the people of Oriental Peru for consider- 
able powers of travel overland. They assert that these fishes, when trapped in a 
pool of water which is drying up after the close of the rainy season, set out by night 
in search of some new body of water, and find it with some degree of assurance by 
a keen moisture sense. Meanwhile the operculum is kept closed over a mouthful 
of water to keep the gills moist. Such a method of conserving a scant water supply 
is not without parallel (see remarks under Hypostomatinae). 
An unusual assemblage of this subfamily was taken from a single small, wood- 
land brook at Iga, flowing into the Rio Itaya above Iquitos. It is probably correct 
to say that they are usually found apart, but here Hoplias, Hoplerythrinus, and 
Erythrinus were taken together. 
TABLE VI. Comparison or THREE ERYTHRINID GENERA 
Character Hoplias Hoplerythrinus Erythrinus 
Head and Head 3.15 in length; eso- | Head 3.2 in the length Head 3.8 in the length; 
body form ciform amiaform 
Mouth Large, extending beyond | Large, extending beyond | Moderate, reaching pupil; 
eye; 6.6 in the length eye; 8.2 in the length 9.3 in the length 
Eye 6.2 in the head 5.8 in the head; actually | 5.8 in head, the smallest 
the largest (head longer) | (but head smallest) 
Depth 5 in length; somewhat 4.5in length; more robust 4.5 in length; more robust 
slender 
Caudal Height 7.7 in the total | 7.5 in the length; moder- 5.6 in the length; robust 
peduncle length; moderate ate 
Scale count 5—42—7; small smooth | 3—37—4; smooth large, 3—36—33; large, rough- 
thin, close ish, conspicuous 
Fins: Dorsal a straight crest | Dorsal rounded Triangular, antepenulti- 
mate ray the longest 
Pectorals ventrals anals | Pectorals, ventrals anals . Pectorals moderately, 
rounded rounded anals, ventrals sharply 
pointed 
Colors Many, smaller, clouded, | Uniform, darker red Larger, deeper red spots, 
reddish spots above, black lateral cloudier and more confluent 
band, uniform lighter be- 
low 
Fin colors All fins spotted, forming  Pectorals  reddest, anal | Darker on all distal borders, 
broken cross bars spotted, ventrals light shading to lighter proxi- 
mally 
