FISHES 99 



2. 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 

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

 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; 

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

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

 the smallest of known fishes. 



b 



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



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. 



3. MoUienisia 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 light 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 

 and with a series of spots; tail fin with round spots;. rays of dorsal 

 fin 15 to 16; anal 8; scales 26-9 or 10: South Carolina to Mexico, in 

 swamps and streams; very common. 



Family 3. Amblyopsidae. — The blind fishes. Body elongate, com- 

 pressed behind; head long, depressed; mouth large; premaxillaries form- 



