Family XI. Pceciliidje. 145 



long, coiled on the right side ; anal fin of the male modified into an intro- 

 mittent organ; gill rakers short, about equal to diameter of pupil; 

 vertebrae 26 to 28; sexes similar in size and color. This genus com- 

 prises, so far as known at present, three species. They are small 

 fishes, none exceeding 2 inches in length. The two species taken in 

 eastern Mexico live in ponds or bayous among water-plants ; to collect 

 them successfully the net must be heavily leaded so as to rake well 

 the bottom. 



So far as color markings are concerned these fishes are more va- 

 riable than any others known to me. Viviparous. 



KEY TO THE SPECIES OF PLATYPGECILUS. 



a. Body deep, compressed, its depth 2^ to 2^. page 



b. Caudal peduncle deep, its least depth t, 2 A in 



the length of the body; depth of body 2]/^ maculatus 145 



bb. Caudal peduncle slender, its least depth 5 in 

 the length of the body; depth of body 2 l / 2 



to 2^ variatus 1 46 



aa. Body slender, elongate, its depth 3% nclsoni 147 



135. Platypoecilus maculatus Giinther. 



Platypcecilus maculatus Giinther, Cat., vi, 350, 1866, Mexico: Gar- 

 man, Memoirs, Mus. Comp. Zool., 1895, 48; Mexico: Jordan & 

 Evermann, Bull. 47, U. S. Nat. Mus., 1896, 686. 



Lowland streams of Mexico which empty into the gulf south of 

 the city of Vera Cruz. (El Hule ; Ob'spo ; Perez.) 



Head 3}{; depth 2^; D. 10; A. 7; scales 9-23. Body deep, com- 

 pressed; profile from tip of lower jaw to dorsal fin a straight line, the 

 highest point at origin of dorsal fin; head rather small; interorbital 

 area flat, its width 2 in length of head; lower jaw slightly the longer; 

 eye 3 in head; snout 3^ in head; teeth loose, small, conical, in a single 

 series in each jaw; dorsal fin slightly in advance of anal, its origin 

 midway between base of caudal and posterior margin of the eye; 

 longest dorsal ray (?) i}4 in the head to (6) 1% in head; caudal 

 peduncle very deep, its least depth 3^ in the length of body; dis- 

 tance between the last dorsal ray and base of caudal slightly less than 

 the least depth of the caudal peduncle; caudal fin rounded; anal fin 

 with falcate margin, its first rays (?) x% in the head; tips of pectorals 

 reaching middle of ventrals, 1^3 in head; ventrals reaching past anal, 

 x% in the length of head; intestinal canal elongate, coiled on the 

 right side in 10 or 12 coils; gill rakers short, the longest about equal 

 to diameter of the pupil ; vertebras 14+12=26; anal fin of the male 

 modified into an intromittent organ, its length 1% in the length of 

 the head. 



