258 FISHES OF WESTERN SOUTH AMERICA 
Type: Anacyrtus guatemalensis Giinther 
Mexico to Argentina, in lowlands, but reaching several thousand feet elevation. 
Teeth small and conical or tricuspid, in a single series on the maxillary and 
sides of the mandibles, in two imperfect series on the premaxillary, and sometimes 
on the front of the mandible; middle premaxillaries slightly larger; maxillary with 
or without teeth along its entire length; anterior mandibular teeth and one on each 
corner slightly enlarged; several larger tooth-like prongs extending forward from 
the upper jaw at the margin of the lip; maxillary sometimes the same; lower jaw 
with 2—4 prongs directed forward. 
Cheeks almost entirely overspread by the suborbitals; gill-membrane free 
from the isthmus; gill-rakers similar on the two limbs, strong, long, few in number; 
pharyngeals with short, stiff rakers; scales small, cycloid; dorsal over origin of anal 
fin, which is very long (42-57 rays); pectorals overlapping ventrals; preventral area 
flattened; tongue free; lateral line complete; alimentary canal short. 
324. ROEBOIDES MYERSI Gill 
Roeboides myersii Gill, 1870, Proc. Acad. Nat. Sci. Phila., XXII, 92; 
Cope, 1871 (1872), Proc. Acad. Nat. Sci. Phila., XXIII, 265; 
Cope, 1878, Proc. Amer. Phil. Soc., XVII, 686, Orton and Hauxwell collections, Peruvian 
Amazon; 
Fowler, 1906 (1907), Proc. Acad. Nat. Sci. Phila., LVIII, 455, fig. 45; 
Higenmann and Ogle, 1907, Proc. U. S. Nat. Mus., XX XIII, 32; 
HKigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 455; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sci. Phila., XCI, 270, one, 101 mm., Contamana. 
Anacyrtus myersii Steindachner, 1882 (1883), Denksch. KIX. Akad. Wiss. Wien, XLVI, 14, Rios 
Huallaga and Maranon, two. 
Peruvian Amazons 
325. RoEBOIDES AFFINIS (Giinther). 
Anacyrtus affinis Giinther, 1868, Proc. Zool. Soc. London, 246, two, four inches, Rio Huallaga; 
Giinther, 1868, Ann. Mag. Nat. Hist., 481. 
Roiboides rubrivertex Cope, 1871 (1872), Proc. Acad. Nat. Sci. Phila., X XIII, 265, Peruvian Amazon 
or Ucayali, Perkins collection. 
Roeboides (Cynocharax) affinis Fowler, 1906 (1907), Proc. Acad. Nat. Sci. Phila., LVIII, 457, fig. 46. 
Roeboides affinis Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 445; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sci. Phila., XCI, 269, seven, 114-164 mm., lower 
Ucayali. 
Amazon and Orinoco basins 
326. ROEBOIDES BICORNIS Cope 
Roeboides bicornis Cope, 1870, Proc. Amer. Phil. Soc., XI, 564, fig., Pebas, Hauxwell collection; 
EKigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, IIT, 445; 
Fowler, 1939 (1940), Proc. Acad. Nat. Sci. Phila., XCI, 268, three, 78-102 mm., lower Ucayali. 
Roeboides (Cynocharax) bicornis Fowler, 1906 (1907), Proc. Acad. Nat. Sci. Phila., LVIII, 458, 
fig. 47. 
Rios Maranon and Ucayali 
