94 HAPLOMI. 



Synopsis of the Mexican and Central-American Species. 

 . I. Dorsal fin with 7 to 12 rays^ its origin posterior to that of the anal. (Gambusia.) 



A. Anal fin similar to the dorsal^ rounded or obtuse^ the middle rays the longest. (? G. tri- 



dentiger.) 



1. End of anal below anterior part or middle of dorsal ( ? ) ; no dark cross-bars on the 



body. 

 Diameter of eye 3 to 3^ in the length of head (in specimens measuring up to 



70 mm.) 1. gracilis. 



Diameter of eye 2|^ to 2| in the length of head (in specimens measuring up to 



50 mm.) 2. bonita. 



2. End of anal nearly below origin of dorsal. 



4 or 5 narrow blackish cross-bars on each side 3. fasciata. 



7 or 8 brownish vertical bars on the posterior part of the body 4. tridentiyer . 



B. Anal fin dissimilar to the dorsal, pointed, the anterior rays the longest. 



1. Pectoral nearly as long as the head, extending to the origin of anal . 5. nicaraguensis. 



2. Pectoral shorter than the head, not reaching the anal. 



a. Dorsal witli 8 or 9 rays. 



Length of head 4 to 4i in the length of the fish (in specimens of 25 to 50 mm.) ; 



29 to 31 scales in a longitudinal series 6. infans. 



Length of head 3-i to 3f in the length of the fish (in specimens measuring up 



to 45 mm.) ; 28 scales in a longitudinal series 7. episcopi. 



b. Dorsal with 10 to 12 rays 8. annedens. 



II. Dorsal fin with 11 to 17 rays, its origin in advance of that of the anal. (Pseudoxiphophorits.) 



A. Origin of anal below or a little in advance of middle of dorsal ; no dark spot above the 



pectoral. 

 Dorsal with 12 to 14 rays, its origin equidistant from tip of snout and base or 



anterior part of caudal 9. terrabensis. 



B. Origin of anal below anterior part of dorsal ; a dark spot above the pectoral. 

 Dorsal with 11 to 13 rays, its origin equidistant from tip of snout and middle 



or posterior part of caudal 10. jonesii. 



Dorsal with 13 to 17 rays, its origin about equidistant from tip of snout and 



base of caudal 11. bimaculata. 



1. Gambusia gracilis*. 



Xiphophorus gracilis, Heck. Sitzungsb. Ak. Wien, i. 1848, p. 300, t. 9. figs. 3-4 '. 



Gambusia affirds, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. G80 ' ; Meek, Publ. Columbian 



Mus., Zool. V. 1904, p. ]30\ 

 Gambusia nobilis, Jord. & Everm. t. c. p. G82 '. 

 Gambusia gracilis, Jord. & Everm. t. c. p. 683 '. 



Depth of body 3 to 4 in the length, length of head 3| to 4. Snout as long or nearly as long as eye, the 

 diameter of which is 3-3^ in tlje length of head. Interorbital width about equal to the distance from 



* For the extensive synonymy of this species, see Jord. & Everm. pp. G81-683, and Garm. Mem. Mus. 

 Comp. Zool. xix. 1895, pp. 82-85 (&'. Iwlhrool-ii, patriwlis, and rjracilis). 



