Carl L. Hubbs 



M^. — Gonopodium rather short; ray 4 curved more or less back- 

 ward at tip Brachyrhaphis. 



M-. — Gonopodium rather longer and more slender; ray 4 curved 

 forward at tip. 

 N^. — Tip of gonopodium gently recurved; ray 5 evenly and 



gently curved; serrated segments of ray 4 numerous 



Priapichthys." 



N-. — Tip of gonopodium abruptly curved forward to form a 

 hook-like appendage ; ray 5 arched backward behind the 



few serrae of ray 4 Panamichthys.^^ 



L-. — Anterior branch of ray 4 alone entering into the formation of 



the specialized forward-curved tip of the long gonopodium (see 



figure 2). 



O^. — Terminal segment of ray 4 greatly elongate; anterior edge 



of ray 4 roughened, the posterior edge with numerous serrae. 



Teeth strictly conical, and mouth with a developed lateral 



gape. Dorsal fin much longer and inserted farther forward 



than anal. Size of iish moderate. Sexual dimorphism slight 



Pseudoxiphophorus. 



O'-'. — Terminal segment of ray 4 much less notably enlarged; ante- 

 rior edge of ray 4 smooth, the posterior edge with few serrae 

 (see figure 2). Teeth somewhat compressed, the mouth more 

 strictly transverse. Dorsal fin about equal in size and oppo- 

 site in insertion to anal. Size minute. Sexual dimorphism 



sharp Heterandria. 



K.^ — Rays 4 and 5 not contiguous distally, separated by a notch in 

 the membrane; the finely segmented tip of the anterior branch 

 of ray 4 and the elongated terminal segment of ray 3 together 



supporting a small knob at tip of fin Priapella. 



J2. — Ray 3 with a short, suberect, curved spur near tip ; anterior branch 

 of ray 4 with a much enlarged node somewhat resembling the 



"elbow" of the Gambusiini Allogambusia.^^ 



2. — Ray 3 with developed serrae along its anterior edge ; ray 3 without 



trace of any processes other than the serrae; anterior branch of ray 



4 curved forward distally (straight in Alloheterandria), and alone 



extended to the extreme tip of the gonopodium. Teeth conical or 



compressed. 



P^. — Ray 3 abruptly hooked forward and upward at tip ; anterior branch 



of ray 4 slender throughout, and without an enlarged terminal 



segment;, the posterior branch of ray 4 with the serrae weak, few, 



and widely separated from tip of ray. Teeth conical 



Darieiiiclithys.^' 



P2. — Ray 3 scarcely curved forward at tip. 



^'^ Priapichthys Regan. Type (as designated by Jordan), Gambusia annectcns, the 

 only species the gonopodium of which was known to Regan. The other species which 

 have been referred to Priapichthys are not strictly congeneric with Priapichthys 

 annectcns. 



11 Panamichthys Hubbs, new genus. Type species, Priapichthys panamcnsis Meek 

 and Hildebrand {Pub. Field Mus., Zool, 10, 1916, p. 322). One species, P. panamcnsis. 



1- Allogambusia Hubbs, new genus. Type species, Gambusia tridcntigcr Garman, 

 Mem. Mus. Comp. Zool, 19, 1895, p. 89, pi. 4, fig. 10 (Priapichthys tridcntigcr Meek 

 and Hildebrand, Puhl Field Mus., Zool, 10, 1916, p. 320, fig. 6J. Two species, A. 

 tridentiger Garman and A. cana Meek and Hildebrand. 



13 Darienichthys Hubbs, new genus. Type species, Gambusia daricnsis Meek and 

 Hildebrand, Puhl. Fi^ld Mus., Zool., 10, 1913, p. 88 {Priapichthys dariensis, Meek and 

 Hildebrand, ibidem, 10, 1916, p. 321, fig. 7). One species known, D. dariensis. 



