104 THE AMERICAN CHARACIDAE. 
Moenkhausia collettii E1GENMANN, Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 438; Mem. Car- 
negie mus., 1912, 6, p. 328. 
HapsitTat. — Amazons and Guiana. 
Specimens examined. 
Catalogue Number of 
number specimens Size in mm. Locality Collector 
20952 36 37-63 Jatuarana Navez 
20711, 20721 20 20-59 Villa Bella Agassiz 
20812 3 37-49 Tea James 
20840 3 3140 ? ? 
20843 41 about 34-54 Obidos Bentos 
1324 C. 11804 I. 19 43-58 Wismar, Demerara River Eigenmann 
1326 C. 11807 I. 5 34-39 Malali, Demerara River Shideler 
1327 C. 11810 I. 136 40-61 Rockstone, Essequibo River Eigenmann 
1328 C. 11806 I. 12 37-59 Gluck Island at Rockstone Eigenmann 
1329 C. 11808 I. 5 41-56 Crab Falls, Essequibo River Eigenmann 
1330 C. 11803 I. 19 338-46 Konawaruk, Essequibo River Eigenmann 
1331 C. 11809 I. 41 35-66 Tumatumari, Potaro River Eigenmann 
1332 C. 11801 I. 100+ 24-68 Erukin, tributary of Potaro Eigenmann 
River, below Amatuk 
1333 C. 1 63 Amatuk Cataract Eigenmann 
1334 C. 3 3840 Tusaca Pan, Rupununi Grant 
3739 C. 111 largest 58 Braganca Haseman 
3740 C. 16 45-50 Bastos Haseman 
3741 C. 2 53-56 Manaos Haseman 
3742 C. 5 40-56 Maciél, Rio Guaporé Haseman 
Head 3.7-3.8; depth 2.6 in gravid females to 3.3 in males, 3.75 in some 
specimens from Guiana; D. 11 (rarely 10 or 12); A. usually 33 or 341; scales 
5-34-34; eye 2.5-2.75; interorbital about 3 in head. 
Compressed, dorsal and ventral profiles equally curved, without humps or 
depressions; preventral area rounded; postventral area compressed or narrowly 
rounded; predorsal area keeled for at least half the distance from the dorsal 
to the occipital process; a median series of nine or ten predorsal scales extend- 
ing from the dorsal to the occipital. 
Occipital process extending about one fifth of the distance from its base to 
the dorsal, bordered by two or three scales; interorbital convex in the middle, 
with lateral grooves; frontal fontanel narrower and about three fourths as long 
as the parietal; second suborbital leaving a naked area on the cheek, widest 
1 Of the Amazon valley specimens one has nineteen anal rays, three have twenty, five twenty-one, 
six twenty-two, thirty-four, twenty-three, twenty-eight, twenty-four, eleven twenty-five, and five twenty- 
six. Of forty-one Guiana specimens three have twenty-one anal rays, sixteen twenty-two, sixteen twenty- 
three, and six twenty-four. 
? Rarely 33 and 35. 
