Dec. 28, 1916. Fishes of Panama — Meek and Hildebrand. 327 



Xiphophorus gillii Kner & Steindachner, Abhandl. K. Bayer. Ak. Wiss. 



Munchen, X, 1864, 28, PI. IV, fig. i (Rio Chagres, Panama). 

 Plaiypcecilus mentalis Gill, Proc. Ac. Nat. Sci. Phila., 1876, 335 (Panama) ; 



Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 686. 

 Poecilia houcardi Steindachner, Sitzb. K. Ak. Wiss. Wien, LXXVI, 



1878, 386, PI. Ill, figs. 2 & 3 (Colon, Panama); Jordan & Evermann, 



Bull. U. S. Nat. Mus., XLVII, 1896, 695; Gilbert & Starks, Mem. 



Cal. Acad. Sci., 1904, 51 (Streams near Panama). 

 Pcecilia gillii Garman, Mem. Mus. Comp. Zool., XIX, 1895, 63 



(Panama). 

 Mollienisia sphenops Regan, Proc. Zool. Soc. London, 1913, 1012, fig. 



173, F (in part); Henn, Ann. Carnegie Mus., X, 1916, 136 (Carta- 

 gena, Colombia). 



Head 3.15 to 4; depth 2.65 to 3.75; D. 10 or 11; A. 10; scales 27 to 30. 



Body compressed; head depressed, flat above; snout broad, its 

 length 3.2 to 4 in head; eye 3.1 to 3.9; interorbital 1.85 to 2.4; mouth 

 small, the cleft transverse; teeth in the outer series slender, movable, 

 somewhat broadened and hooked at apex; inner teeth in a band, small, 

 tricuspid; scales moderate, cycloid, 8 longitudinal rows between base of 

 dorsal and anal; origin of dorsal in female a little in advance of anal, and 

 somewhat nearer end of snout than tip of caudal, its base about equal to 

 length of longest rays; in the male this fin is much higher and the base 

 is equal to about two-thirds the length of the longest rays; caudal fin 

 scaly at base, its margin rounded; anal fin in female inserted about 

 equidistant from end of snout and tip of caudal, the anterior rays not 

 produced; in the male this fin is inserted equidistant from end of snout 

 and base of caudal, the produced portion 1.2 to 1.45 in head, the first 

 and the two branches of the second produced ray of about equal length, 

 the anterior ray bearing a small antrorse hook at apex, the third with a 

 process directed downward and backward at its apex; in advance of the 

 intromittent organ lies a sort of hood which is not attached to the distal 

 portion of this organ; ventral fins normal in the female, reaching vent; 

 in the male the first articulated ray is produced, reaching notably 

 beyond base of anal; pectoral fins rather long, 1.05 to 1.7 in head. 



Color olivaceous, dorsal and caudal fins with dark dots. The color 

 of specimens from salt and brackish water is more variable than those 

 taken in fresh water. The markings on Atlantic slope specimens are 

 more distinct than on those from the Pacific side. The color markings 

 of specimens from Colon agree with those from Vera Cruz, Mexico; 

 most of the specimens have a black spot on each scale forming lines 

 along the rows. These spots are seldom present on the Pacific side 

 specimens and when present are not very distinct. The males often have 



