lo Carl L. Hubbs 



2>. — Mouth with a lateral cleft; bones of lower jaw firmly connected; teeth 



fixed and conical Leptorhaphis. 



2r. — Mouth with the cleft transverse and vertical; bones of the lower jaw 

 loosely connected ; teeth movable and somewhat compressed, 

 a^. — Body deep and the form not distorted. Dorsal inserted farther for- 

 ward than anal. Gonopodium longer, reaching nearly or quite to 

 caudal base when depressed; posterior branch of ray 4 not nearly 



reaching tip of fin Pliallichthysi.21 



a^. — Body slender, and distorted in form, as usual in Gambusia. Dorsal 

 inserted farther back than anal. Gonopodium of moderate length, 

 not reaching caudal base when depressed ; posterior branch of ray 



4 nearly reaching tip of fin Poeclliopsis.-- 



Y2. — Well developed serrac of ray 4 directed forward and outward in part. 



Other characters as here given for Poeciliopsis Phalloptychus. 



X^. — Gonopodium with two prominent horn-like appendages, — one, like the 

 excrescence on a pelican's bill, on the front edge of ray 3; the other a long 

 curved horn attached at base to posterior edge of ray 4. Other characters 



as here given for Leptorhaphis Xenophallus.-^ 



B^. — Pelvic fins enlarged and modified in the male, the first ray with a soft swollen 

 tip, the second ray thickened and usually much elongated. Ray 5 of anal fin 

 in male (the last ray of the gonopodium) forming a trough posteriorly, the 

 two sides of the posterior branch of the ray being widely separated, and more 

 or less twisted to one side; ray 3 with a membranous swelling along anterior 



margin (characters not known for the Pamphoriini) Poeciliinae. 



b\ — Gonopodium elongate, about one-third as long as the body. Bones of the 

 lower jaw more firmly united. Inner ventral rays abruptly shorter than the 

 second ray. (Tribe Pamphoriini.)^ 

 c^. — Teeth of outer series slender, pointed; bones of lower jaw firmly united... 



Pamphorichthys. 



c^. — Teeth of outer series broad incisors; bones of lower jaw somewhat less 



firmly united Pamphoria. 



b^. — Gonopodium short. Bones of lower jaw loosely united. Teeth of outer series 

 rather slender, spatulate. 

 d^. — Membranous swelling on front of gonopodium not forming a definite pre- 

 puce-like hood; ray 3 ending in a very large and strong hook, about the 

 end of which the tip of the anterior branch of ray 4 is curved; posterior 

 branch of ray 4 with serrae both distal and proximal to tip of ray 5; ray 

 5 arched backward toward tip (see figure 4). Inner rays of ventral of 

 male not abruptly shorter than the second ray. (Tribe XiphopliorinL) ^ 

 e^. — Ray 5 not ending in a hook. Caudal alike in the two sexes; dorsal fin 



shorter, with 9 to 1 1 rays Platypoecilus. 



e-. — ^Ray 5 ending in a backward-directed hook. Lower rays of caudal fin in 

 the male ending in a long, sword-like appendage ; dorsal fin longer, with 

 13 to 15 rays Xiphophorus. 



20 Poeciliopsinae Hubbs, new subfamily name. 



-iPhallichthys Hubbs, new genus. . Type species, Poeciliopsis istlnncnsis Regan. 

 Pocciliofsis istlnncnsis from Panama and Poccilia pittieri Meek from Costa Rica are 

 probably identical with Poeciliopsis amates Miller, from Guatemala and Honduras (a 

 specimen from Tela, Honduras, is at hand). 



--Poeciliopsis Regan. Type, Poccilia presidionis Jordan and Culver (as designated 

 by Henn, 1916; not Poeciliopsis isthmcnsis as designated by Jordan, 1920). 



23Xenophallus Hubbs, new genus. Type species, Gamhxisia nmbratilis Meek, Publ. 

 Field Mus., Zool., 10, 1912, p. 70 (type material, from Costa Rica, re-examined). 



2* Pamphoriini Hubbs, new tribe name. This tribe perhaps belongs in the Gam- 

 busiinae, the distinctive features of its two genera not being well known. 



25 Xiphophorini Hubbs, new tribe name. 



