eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 455 



Caudal spots always along the rays, rarely confluent into zigzag cross-bars; 

 anal plain or spotted, dorsal spotted. 



299. Rivulus lanceolatus Eigenmann. (Plate LXIV, fig. 1.) 

 Rivulus lanceolatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 51; Repts. Prince- 

 ton Univ. Exp. Patagonia, III, 1910, 455. 



Type unique, 42.5 mm. Rockstone. (Carnegie Museum Catalog of Fishes 

 No. 1084.) 



300. Rivulus frenatus Eigenmann. (Plate LXIV, fig. 2.) 



Rivulus frenatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 51; Repts. Princeton 



Univ. Exp. Patagonia, III, 1910, 455. 



Type unique, 28 mm. Gluck Island. (Carnegie Museum Catalog of Fishes 



No. 1085.) 



Subfamily Anablepin^e. 



Anableps Gronow. 

 Anableps Gronow, Mus. Ichth., II, 1763, 7.— Scopoli, Intr. Hist. Nat., 1877, 450. — 



Bloch, Ausl. Fische, VIII, 1794, 7. 



The Four-Eyes, the largest of the Potciliidce. Eyes in elevated sockets, the 

 pupil divided by a horizontal cross-partition. Gives birth to living young several 

 inches long. The sexes are dextral and sinistral, a right-sided male mating with a 

 left-sided female. Anal of the male with a scaly tube. 



Abundant on the surface of canals in brackish water, and capable of rapid 

 locomotion by skipping along the surface. 



Two species are brought to the Georgetown market. Only females were ob- 

 tained by me, most of them with young. 



Key to the Guiana Species of Anableps. 



a. Space between the upper edges of the orbital ridges much greater than the eye; sides with conspicuous 



violet stripes. Scales 50-55, tr. 1 1 ; caudal rounded, but very little oblique; snout truncate. . . anableps. 



aa. Space between the upper edges of orbital ridges equal to the diameter of the eye; sides with obscure stripes; 



scales 81-90, tr. 17-18; caudal very obliquely rounded; snout pointed microlepis. 



301. Anableps anableps (Linnaeus). 



Cobitis anableps Linnaeus, Syst. Nat., ed. 10, I, 1758, 303. 



Anableps anableps Garman, "Cyprinodonts," in Mem. Mus. Comp. Zool., XIX, 

 1895, 77. — Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 457. 



Anableps tetrophthalmus Bloch, Ausl. Fische, VIII, 1794, 7, pi. 361. — Muller and 

 Troschel, in Schomburgk, Reisen, III, 1848, 632 (mouths of streams). — 

 Eigenmann and Bean, Proc. U. S. Nat. Mus., XXXI, 1907, 667 (Amazon). 



