Jordan and Ever mann. Fishes of North America. 693 



9 ; scales 28-9 or 10. Origin of dorsal midway between root of caudal 

 and occiput, over twelfth scale of the lateral series. Origin of dorsal 

 slightly in advance of that of anal ; dorsal fin rather small ; anal very 

 small ; basal half of the caudal scaly. Tail compressed, high, its least 

 depth being equal to, or rather more than, length of head without snout. 

 Eight longitudinal series of scales on each side of the tail. Brownish 

 green ; each scale of the 4 middle series of the trunk with a small central 

 black spot ; dorsal with numerous round blackish spots; caudal with an 

 indistinct whitish cross-band near its hind margin. Males compara- 

 tively scarce ; they want the black spots on the sides, and have the anal 

 fin transformed into an intromittent organ. Southern Mexico and Cen- 

 tral America; Chiapas, Duenas, Vera Paz, and Amatitlan. (Giinther.) 



Piecilia mexicana, STEINDACHNEK, Sitzber. Akad. Wiss. Wien, 1863, 178, Southern Mexico; 

 GtiNTHER, Cat., vi, 340, 1866. 



1025. P<ECILIA THERMALIS, Steindachner. 



Head 3i ; depth 3. D. 9 or 10 ; A. 8 or 9 ; scales 30-9. Width of 

 interorbital space equal to distance between front margin of orbit and 

 gill opening; the eye a little longer than snout, 3 in head, a little more 

 than half the interorbital space. Origin of dorsal midway between 

 root of caudal and occiput, over twelfth scale of the lateral series ; ori- 

 gin of anal opposite third ray of dorsal in the female ; dorsal fin of 

 moderate size; anal small; caudal scaly at the base only. Tail com- 

 pressed, moderately elongate, its least depth being somewhat less than 

 the length of the head without snout. Seven longitudinal series of 

 scales on each side of the tail. Greenish ; a faint darker streak along 

 each series of scales ; frequently a round blackish spot in the middle of 

 the side in females. Male with the dorsal fin elevated, and the longest 

 ray at least as long as the head without snout; this fin ornamented 

 with large, ovate black spots, occupying the lower half of the fin, and 

 sometimes confluent into one large patch. Anal fin modified into an intro- 

 mittent organ, and advanced to between the ventrals and in front of the 

 dorsal. Tail strongly compressed, and comparatively rather higher than 

 in the female. Interradial membrane of the caudal fin with oblong black 

 spots, nothing of which is visible in the female. Warm springs in Central 

 America. (Giinther.) (thermalis, pertaining to heat.) 



Paecilia thermalis, STEINDACHNER, Sitzber. Akad. Wiss. Wien, 1863, 181, warm springs in Cen- 

 tral America; GUNTHER, Cat., vi, 341, 1866. 



Gambusia* modesta, TaoscHEt, Miiller's Eeise in Mexico, in, 639, 1865, Mexico; no locality 

 given. 



1026. PtECILIA CHISOYENSIS, Giinther. 



Head4; depth 3^. Eye equal to snout, 3i in head, and more than 

 half width of interorbital space. D. 9 or 10 ; scales 29-9. Free portion 

 of tail elevated, its least depth | its own length, and more than length 

 of head without snout. Origin of dorsal fin nearer occiput than 



* Gambusia modesta, : D. 10; A. 9; P. 16. Length of type (male) 1% inches; depth 4% in total 

 length; dorsal inserted over last rays of anal, as high as the body below it; anal equally high- 

 pectorals reaching end of base of anal; caudal rounded. Brown, with irregular dark spots on 

 back; no net-like markings formed by edges of scales. Troschel. 



