Io6 VERTEBRATE ANIMALS OF THE UNITED STATES 



with darker; a very narrow, often indefinite, lateral stripe; rays of 

 dorsal fin 7 to 9; anal 8 to 10; scales 29 to 32-8 to 10: marshes of the 

 Atlantic and Gulf coasts from Delaware to Mexico and northward to 

 Kentucky, Tennessee and southern Illinois in the Mississippi Valley; 

 in brackish and fresh water; very common in the south. 



6. Heterandria Agassiz. Top minnow. Body rather stout; mouth 

 very small; both jaws with a single series of teeth; scales large; anal 

 fin in advance of the dorsal, and in the male modified to form an intro- 

 mittant organ; viviparous: 6 species of very small fish in swamps in 



b 



Fig. 47. — Gambusia affinis: a, male; b, female {from Fishes of Illinois). 



the southern States, West Indies and Mexico; 2 species in the United 

 States. 



H. formosa Ag. Length 20 to 25 mm.; head 3.5; depth 3.75; color 

 brownish olive, with a wide black lateral band crossed by 6 to 9 vertical 

 bars; a black spot on the dorsal and anal fins; rays of dorsal fin 7; 

 anal 6 to 9; scales 24 to 28: South Carolina to Florida; very common in 

 swamps and ditches, often in company with Gambusia affinis; one of the 

 smallest of known fishes. 



H. occidentalis Baird & Girard. Length 65 mm.; head 3.5; depth 4; 

 color brownish, dotted with black, with a black lateral stripe; rays of 

 dorsal fin 7 or 8; anal 9 or 10; scales 29-8: southern Arizona; common 

 in springs and ditches. 



7. Mollienisia LeSueur. Body rather stout; mouth small; both 

 jaws with a narrow band of small teeth; scales large; anal fin behind the 

 dorsal and modified in the male to form an intromittant organ: 4 

 species in the southern States and Mexico; i species in the United States. 



M. latipinna LeS. Length 75 mm.; head 3.5 to 4; depth 2.5 to 3; 

 color hght green, in the male marbled with darker and spotted, with 

 longitudinal lateral series of blackish spots ; dorsal fin very long and in 

 the male very elevated, exceeding the height of the body, translucent 



