41 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 Pwczlia 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. 
Peecilia butleri. Rather common. 
Pecilia presidionis. Very common. 
Thyrina crystallina. Rather common. 
Agonostomus nasutus. Very common in ripples. 
Siphostoma starksii. Common in alge in sluggish water. 
Centropomus ensiferus. Common in cut-offs of rivers. 
Centropomus pedimacula. Scarce. 
Eucinostomus gracilis. Common. 
Xystema cinereum. Not rare. 
Heros beani. Common in deep places. 
Philypnus lateralis. Common (young very common). 
Eleotris equidens. Scarce. 
Dormitator latifrons. Common. 
Awaous taiasica. Common. 
Citharichthys gilberti. Not rare in river; colors very bright. 
Achirus mazatlanus. Very common. 
Achirus fonsecensis. Scarce. 
54. Pecilia presidionis Jordan & Culver, n. sp. Plate 
KIM: 
In the clear waters of the Rio Presidio, about Presidio; 
with the preceding, and still more abundant. 
Mead 4 -sedepil y= to. 4.50 D7 ore; anale7 >) scales 
28-9; eye equal to snout, 3% in head; interorbital 2; 
Gaudal 1 to 34; pectoral 1%.) Body rather elongate, 
shaped as in a Fundulus, the profile scarcely rising to 
dorsal. 
Teeth much as in Pecilia butler’, the outer smaller 
