FISHES OF SINALOA. 413 



with a dark spot behind pectoral; lower fins bright orange, 

 caudal nearly plain; dorsal speckled as in male. Form 

 similar to that of male, deeper than in Poecilia -presidionis. 



Alcoholic specimens show no dark spot behind pectoral 

 and only a few specimens show traces of orange colora- 

 tion on fins. 



The following is a list of the species of fishes found in 

 the fresh waters of Rio Presidio about Presidio and Villa 

 Union: 



Stardinella stolifera. Scarce. 



PcBcilia butleri. Eather common. 



Poecilia presidionis. Very common. 



Thyrina crystallina. Eather common. 



Agonostomtis nasiitus. Very common in ripples. 



Siphostoma starksii. Common in algae in sluggish water. 



Centropomus ensiferiis. Common in cut-offs of rivers. 



Centropomus pedimacula. Scarce. 



Eucinostomus gracilis. Common. 



Xystfema cinereum. Not rare. 



Heros beani. Common in deep places. 



Philypnus lateralis. Common (young very common). 



Eleotris asquidens. Scarce. 



Dormitator latifrons. Common. 



Awaous taiasica. Common. 



Citharichthys gilberti. Not rare in river; colors very bright. 



Achirus mazatlanus. Very common. 



Achirus fonsecensis. Scarce. 



54. Poecilia presidionis Jordan & Culver, n. sp. Plate 

 xxix. 



In the clear waters of the Rio Presidio, about Presidio; 

 with the preceding, and still more abundant. 



Head \\; depth 3^ to 4I; D. 7 or 8 ; anal 7; scales 

 28-9; eye equal to snout, 3^^ in head; interorbital 2; 

 caudal i to i|; pectoral i}^. Body rather elongate, 

 shaped as in a Fundulus, the profile scarcely rising to 

 dorsal. 



Teeth much as in PcBcilia hutleri, the outer smaller 



