132 THE AMERICAN CHARACIDAE. 
translucent, the caudal bright red, upper parts tinged with red, basal part of 
dorsal and anal lobe below the black spots bright yellow, the distal parts 
milk-white. 
2. PRISTELLA AUBYNEI Eigenmann. 
Plate 13, fig. 1. 
Pristella aubynei ErceENMANN, Ann. Carnegie mus., 1909, 6, p. 24 (Lama Stop-Off); Rept. Princeton 
univ. exped. Patagonia, 1910, 3, p. 437; Mem. Carnegie mus., 1912, 5, p. 330, pl. 45, fig. 4. 
Hasitrat.— Lamaha Basin, British Guiana. 
Specimens examined. 
Number of 
Catalogue number specimens Size in mm. Locality Collector 
1042 C. Type 1 50 Lama Stop-Off Eigenmann 
1043 C. 11735 I. 203 20-50 Lama Stop-Off Eigenmann 
1044 C. 11736 I. 50 28-46 Cane Grove Corner Eigenmann 
1045 C. 11737 I. 21 35-49 Maduni Stop-Off Eigenmann 
This species is very abundant in the canal from Cane Grove Corner to 
Maduni Creek Stop-Off, British Guiana. 
This species is placed in the genus with P. riddlei because in the technical 
characters they agree. There is every probability that they are not immedi- 
ately descended from the same ancestor. 
Head 3.75; depth 3.5; D. 10; A. 16-18; scales 6-31 to 33-3 rarely 4; 
7 to 9 pores in the lateral line; eye 2.33; interorbital 3. 
Elongate, heavy forward; ventral profile curved more than the dorsal, 
which is nearly straight to the dorsal, not depressed over the eye; preventral 
area broad, rounded, postventral area keeled; predorsal area narrowly rounded. 
Occipital process triangular, very short, equal to one sixth of the distance 
from its base to the dorsal. Fontanel widest at the base of the occipital process, 
anterior fontanel slightly shorter than the posterior, triangular, its anterior 
pointed end a little in advance of the middle of the eye. Second suborbital 
leaving a wide naked area below, a narrower one behind. Mouth oblique; 
maxillary slender, its anterior margin nearly straight; two and three fourths 
in the head; five teeth in the front series of the premaxillary of which the middle 
one is withdrawn from the line of the rest. Inner series of teeth large, multi- 
cuspid, graduate. Maxillary with numerous similar teeth; lower jaw with four 
or five graduate, multicuspid teeth in front and minute ones on the side. 
Gil-rakers about 6 + 11. 
