PCECILIA. 101 



Siinopsis of the Sj)ecies *. 



I. Origin of anal in advance of that of the dorsal. 



Dorsal 8. Anal 7. 2G scales in a longitudinal series 1. spilurns. 



Dorsal 7-9. Anal 9-11. 27 to 30 scales in a longitudinal series 2. occidentalis. 



Dorsal 9-10. Aual 8-9. 30 to 33 scales in a longitudinal series 3. elonguta. 



II. Origin of anal below or behind that of the dorsal. 



A. Origin of anal below or a little behind that of the dorsal; origin of dorsal ecjnidistant from 



tip of snout and middle or posterior part of caudal ; 26 to 30 scales in a longitudinal 



series. 



Free edge of dorsal fin convex 4. sphenops. 



Free edge of dorsal fin straight 5. salvatoris. 



B. Origin of anal below fourth or fifth dorsal ray; origin of dorsal equi- 



distant from tip of snout and base of caudal; 28 to 30 scales in a 



longitudinal series 0. petenens'is. 



C. Origin of anal below the middle of dorsal ; origin of dorsal equidistant from tip of snout 



and anterior part of caudal ; 23 to 27 scales in a longitudinal series. 

 Depth of body about 2| in the length, length of head about 4 (in specimens of 



50 mm.) , 7. cnuchiana. 



Depth of body 2 to 2-j in the length, length of head 3^ to 33 (in specimens of 



60 mm.) 8. maculuta. 



1. Poecilia spilurus. 



Poecilia spilurus, Gunth. Cat. Fish. vi. p. 345 (1866)'; Jord. & Everm. Bull. U.S. Nat. Mus. 

 slvii. 1896, p. 697'. 



Dejjth of body 3| in the length, length of head 4. Snout a little shorter than eye, the diameter of which is 

 83 in the length of head. Interorbital width equal to the distance from posterior margin of pupil to 

 free edge of operculum. 26 scales in a longitudinal series. Dorsal 8 ; origin about equidistant from tip 

 of snout and posterior end of caudal. Anal 7 ; origin in advance of that of the dorsal ( $ ). Least depth 

 of caudal peduncle the length of head. A blackish spot on each side of the upper part of the tail, at the 

 base of the caudal fin. 



Ilah. Centkal America {Salle ^). 



Here described from the type, the only specimen known, 60 mm. in total length. 



2. Poecilia occidentalis. 



Heterandria occidentalis, Baird & Girard, Proc. Ac. Philad. 1833, p. 390 ^ ; Jord. & Everm. Bull. 



U.S. Nat. Mus. xlvii. 1896, p. 689 \ 

 Girardinus occidentalis, Girard, U.S. Mex. Bound. Surv., Fishes, p. 73, t. 39. figg. 16-19', and 



Proc. Ac. Philad. 1859, p. 119 '. 

 Girardinus sonorensis, Girard, Proc. Ac. Philad. 1858, p. 120 . 



* This synopsis is based on female specimens only. The males of some of the species have not yet been 

 described. 



