41 FISHES OF SINALOA. 413 



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

 caudal nearly plain; dorsal speckled as in male. Form 

 similar to that of male, deeper than in Pcecilia 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 : 



Sardinella stolifera. Scarce. 



Pcecilia butleri. Rather common. 



Pcecilia presidionis. Very common. 



Thyrina crystallina. Rather common. 



Agonostomus nasutus. Very common in ripples. 



Siphostoma Btarksii. Common in alga? in sluggish water. 



Centropomus ensiferus. Common in cnt-offs of rivers. 



Centropomus pedimacula. Scarce. 



Eucinostomus gracilis. Common. 



Xystsema cinerenm. Not rare, 



Heros beani. Common in deep places. 



Philypnus lateralis. Common (young very common). 



Eleotris sequidens. Scarce. 



Dormitator latifrous. Common. 



Awaous taiasica. Common. 



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



Achirus mazatlauns. Very common. 



Achirus fonsecensis. Scarce. 



54. Pcecilia 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 a^\ ; depth 3-i to 4-i; D. 7 or 8; anal 7; scales 

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

 caudal 1 to ii; pectoral 1%. Body rather elongate, 

 shaped as in a Fundulus, the profile scarcely rising to 

 dorsal. 



Teeth much as in Pcecilia butleri, the outer smaller 



