PUNDULUS. 77 



California and which probably enter the rivers of Sinaloa, and others which are not 

 yet known to extend further south than the Rio Grande. 



Synopsis of the Mexican and Central- American Species. 



I. Origin of anal fin below or behind that of the dorsal. (Fundulus.) 



A. 30 to 40 scales in a longitudinal series. 



1. Dorsal 12-14. Anal 13-17. Oviduct not produced into a tube attached to the anal tin. 



a. 32 to 35 scales in a longitudinal series. 



Interorbital width more than \ the length of head ; snout not longer than eye. 1. pachycephalus. 

 Interorbital width \ the length of head or a little less ; snout not shorter 



than eye 2. punctatus. 



b. 36 to 39 scales in a longitudinal series 3. labialis. 



2. Dorsal 10-13. Anal 10-12. Females with the oviduct produced into a tube or sheath 



attached to the anterior anal rays. (? F. vinctus.) 



a. 31 to 34 scales in a longitudinal series. 



Interorbital width \ the length of head, which is 3| in the length of the fish 



(in specimens of 65 mm.) 4. vinctus. 



Interorbital width r the length of head, which is 3? in the length of the fish 



(in specimens of 70 mm.) 5. palUdus. 



Interorbital width I- the length of head, which is 3 in the length of tlie fish 



(in specimens of 100 mm.) 6. similis. 



b. 35 to 39 scales in a longitudinal series. 



Anal fin deep, when laid back extending to or nearly to the base of caudal . 7. heterocliius. 

 Anal fin of moderate depth, when laid back not nearly reaching the caudal . 8. grandis. 



B. 44 to 60 scales in a longitudinal series. 



Dorsal 13. Anal 11. 44 scales in a longitudinal series 9. adinia. 



Dorsal 15. Anal 13. 47 scales in a longitudinal series .10. extcnsus. 



Dorsal 14-15. Anal 13-14. 60 scales in a longitudinal series 11. zebrinus. 



II. Origin of anal fin far in advance of that of the dorsal. (Zvgonectes.). 12. dovii. 



1. Pundulus pachycephalus. 



Fiindidus pachycephalus, Giinth. Cat. Fish. vi. p. 321 (1866) ', and Trans. Zool. Soc. vi. 1868, 



p. 483, t. 84. fig. 6 \ 

 Adinia pachycephala, Jord. & Everm. Ball. U.S. Nat. Mas. xlvii. 1896, p. 660 \ 



Depth of body 3 to 3| in tho length, length of head 3j to 3i. Snout nearly as long as or shorter than eye, 

 the diameter of which is 3^ to 3| in the length of head ; interorbital width more than 4 the length of 

 head. Lower jaw slightly projecting. 32 to 35 scales in a longitudinal series. Dorsal 12 to 14 ; 

 orio-in nearer to base of caudal than to head. Anal 13-15 ; origin below or a httle behind that of the 

 dorsal; no tube attached to the anterior rays. Pectoral f to g the length of head. Caudal subtruncate. 

 Brownish, each scale with an indistinct darker spot ; an indistinct dark lateral band on the posterior part 

 of the body ; vertical fins dusky, the dorsal with a few spots, the anal with a pale margin. 



Hab. Guatemala, Lake Atitlan ^ ^ [Salvin). 



Here described from the types, four females measuring up to 72 mm,, in totallength. 



