178 THE AMERICAN CHARACIDAE. 
Origin of the dorsal as in the related species but origin of the anal on the 
vertical from the third instead of the fifth dorsal ray. 
Entire dorsal dark, anal web, except in the anal lobe, black; some large 
black chromatophores on the anal rays. The sides everywhere thickly peppered 
with conspicuous chromatophores; especially dusky about the origins of the 
anal and ventrals. The scales in the upper half of the region above the anal 
more or less distinctly outlined. Preopercle and second suborbital with brassy 
reflections which are less evident on the scales of the body. 
3. HYPHESSOBRYCON CALLISTUS (Boulenger). 
Plate 24, fig. 3; Plate 79, fig. 13. 
Tetragonopterus callistus BouLENGER, Boll. Mus. univ. Torino, 1900, 15, no. 370, p. 2 (Carandosinho, 
Matto Grosso). 
Hemigrammus melanopterus ExaeNMANN and Kernnepy, Proc. Acad. nat. sci. Phil., 1903, p. 518 
(Arroyos Trementina and Pypucu, Paraguay). 
Hyphessobrycon callistus EXGENMANN, Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 436; ELuts, 
Ann. Carnegie mus., 1911, 8, p. 158. 
Hasirat.— Paraguay Basin in Matto Grosso and Paraguay. 
Specimens examined. 
Catalogue Number of 
number specimens Size in mm. Locality Collector 
10039 I. ! 1 33 (about) Arroyo Trementina Anisits 
10040 I. ? 1 33 (about) Arroyo Pypucu Anisits 
10041 ? 1 28 (about) Arroyo Pypucu Anisits 
3039 C. 8 26-38 Caceres Haseman 
3040 C. 14 33-38 Puerto Suarez Haseman 
3037 C. 4 31-39 (about) Corumba Haseman 
3038 C. 6 25-38 (about) Jauru Haseman 
Head 3.2-3.6; depth 2.33-3; D. 10 or 11; A. 27 to 30; scales 6 to 7.5-5 + 31 
to 33-3.5; eye 2.25 to 2.66 in head, interorbital 3.5 in the head. 
Compressed, deep; depth of head at the base of the occipital process 2, 
or little less, in the greatest depth. Dorsal profile much arched to the origin 
of the dorsal. Dorsal base steeply inclined toward the caudal. Preventral 
region rounded, no regular median series of scales. Predorsal region rounded, 
with a regular median series of 11 scales. 
' Type of H. melanopterus Kigenmann & Kennedy. 
? Paratypes of H. melanopterus Eigenmann & Kennedy. 
