ii6 Field Museum of Natural History — Zoology, Vol. X. 



male easily distinguishes this species from the Mollienisia s. tropica 

 found in the same region. The specimens collected by me are as 

 follows: 



La Junta (14), 38 to 70 mm.; Parismina (11), 58 to 70 mm.; Guapilis 

 (18), 27 to 63 mm.; Virginia (4), 35 to 55 mm. 



Mollienisia sphenops (Cuvier & Valenciennes). 



Poecilia sphenops Cuvier & Valenciennes, Hist. Nat. Poiss., xviii, 

 1846, 130, pi. 526 (Vera Cruz, Mexico); — Regan, Biol. Cent. 

 Amer., 1907, 102, pi. xiii, figs. 3-7, part. 

 Mollienisia sphenops Regan, Ann. & Mag. Nat. Hist., 1913, 1012 



(part). 

 This species is ^videly distributed and varies greatly. The original 

 types were taken at Vera Cruz, Mexico, probably in the salt-water 

 pools there where it is ver}' abundant, and where it grows comparatively 

 large. I did not do any collecting in salt water in Costa Rica, and so 

 did not obtain any specimens, but presume those occurring there are 

 the same as those taken at Vera Cruz, Mexico. 



Mollienisia sphenops tropica (Meek). 



Platypoecilia tropicus Meek, Pub. Field Mus,, Zool. Ser., vii, 1907, 



146 (Turrialba, Costa Rica). 

 Poecilia tenuis Meek, Pub. Field Mus., Zool. Ser., vii, 1907, 147 



(Rio Maria Aguilar, Costa Rica). 

 Poecilia tropica Regan, Biol. Cent. Amer., 1908, 191; Regan, Ann. 



& Mag. Nat. Hist., 1908, 459 (Rio Iroquois). 

 Poecilia sphenops Regan, Biol. Cent. Amer., 1907, 102, part (San 



Jose, Costa Rica); — Regan, Ann. & Mag. Nat. Hist., 1908, 458 



(Volcano of Tenorio). 

 Poecilia spilonota Regan, Ann. & Mag. Nat. Hist., 1908, 460 (San 



Jose, Costa Rica). 

 Poecilia caucana Regan (not Steindachner) , Biol. Cent. Amer., 1908, 



190, pi. 13, fig. 2 (San Jos^ and Rio Maria Aguilar, Costa Rica). 

 Poecilia caudata Meek, Pub. Field Mus., Zool. Ser., vii, 1909, 209 



(Turrubales, Costa Rica). 

 Mollienisia sphenops Regan, Ann. & Mag. Nat. Hist., 1913, 1012 



(part). 

 The inland or fresh-water forms of tliis species or variety found in 

 Costa Rica are very variable, and as a result several species have from 

 time to time been described. The upland forms in general are smaller 



