Fishes of thi-; Order Cyprinodontes 9 



Q^. — Anterior branch of ray 4 with an enlarged terminal segment; 

 posterior branch of ray 4 with the serrae few but strong, extend- 

 ing nearly to tip of ray; serrae of ray 3 short. 

 R^. — Terminal segment of gonopodium not curved, but with a back- 

 ward directed spinelet ; segments of anterior branch of ray 4 

 everywhere slender. Mouth with a lateral cleft ; teeth conical. 



Size of fish small Alloheterandria." 



R-. — Terminal segment of gonopodium strongly curved forward, and 

 without spinelets ; two subterminal segments of anterior branch 

 of ray 4 considerably thickened. Mouth vertical; teeth some- 

 what expanded at tip. Size minute Neoheterandria.^^ 



Q-. — Anterior branch of ray 4 with the terminal segment not enlarged; 

 posterior branch of ray 4 with the serrae more numerous, but 

 not nearly extended to tip of ray; serrae of ray 3 long. Teeth 



incisor-like; mouth without developed lateral cleft 



Pseudopoecilia. 



H-. — Ray 3 with a pair of curved horn-like appendages near tip ; ray 5 with 

 the posterior edge serrate. (Tribe Crirardiiiini.)^" 

 S^. — Bones of the lower jaw firmly united; the teeth fi.xed. 

 T^. — Teeth of the outer row spear-shaped and widely spaced. .. .Toxus. 



T-. — Teeth of outer row chisel-shaped and close-set Glardichthys. 



S^. — Bones of lower jaw loosely connected; teeth of outer row movable, 



spatulate Girardinus. 



T)-. — Terminal segment of ray 3 forming a more or less highly specialized proc- 

 ess. (Tribe Cnesterodontini.)" 

 U^. — Process not trowel-like. 



V^. — Process not forked, nor antler-like. 

 W^. — Process short, with a simple and slight curve ; ray 3 with serrae on 



both edges. Teeth of outer row conic Diphyacantha.^^ 



W". — Process inordinately elongate, with a strong, double curve ; ray 3 

 without developed serrae. Teeth of outer row chisel-shaped, fol- 

 lowed by a single series of conical teeth Cnesterodon. 



V-. — Process forked, and each fork antler-like. Teeth of outer row oar- 

 shaped, slender, followed by a band of villiform teeth Phalloceros. 



U^. — Process trowel-shaped ; a most remarkable structure, formed like a rela- 

 tively immense scoop, with a compressed horn on each side, and attached 



to the fin by a narrow pedicel. Teeth oar-shaped, in a single series 



Phallotorynus.i" 



C-. — Rays of the gonopodium imbricated so as to form an enclosed tube on 



right side of fin (see figure 3) Poeciliopsiiiae. 



X^. — Gonopodium without horn-like appendages; ray 4 not forming a hook at 

 its tip. 

 Y^. — All well developed serrae of ray 4 directed backward. 



1* AUoheterandria Hubbs, new genus. Type species, Gambusia nigroventralis 

 Eigenmann and Henn, Indiana Univ. Studies, No. 16, 1912, p. 26 {Priapichthys nigro- 

 ventralis Henn, Ann. Cam. Mus., 10, 1916, p. 115, fig. 3). In addition to A. nigroven- 

 tralis, Ganibusia calicnsis Eigenmann and Henn, in Henn, /. c., p. 113, may prove to 

 belong to this genus. 



15 Neoheterandria Henn, Ann. Cam. Mus., 10, 1916, p. 117, fig. 5. Haplotype, 

 Neoheterandria elcgans Henn, from Colombia. 



18 Girardinini Hubbs, new tribe name. 



1" Cnesterodontini Hubbs, new tribe name. 



1^ Diphyacantha Henn, Ann. Cam. Mus., 10, 1916, p. 113, fig. 2. Haplotype, Diphy- 

 acantha chocoensis Henn. 



18 Phallotorynus Henn, Ann. Cam. Mus.. 10, 1916, p. 126, figs. 8-13. Haplotype, • 

 Phallotorynus fasciolatus Henn, from Brazil. 



