94 VERTEBRATE ANIMALS OF THE UNITED STATES 



di Teeth in more than one series. 



ei Dorsal fin relatively large, with 12 to 18 rays; 

 bottom fishes, 

 fi Scales relatively large, with 31 to 50 in the lateral 

 line, 

 gi Dorsal fin inserted before the anterior border 



of the anal i . Fundulus. 



g2 Dorsal fin inserted over the anterior border 



of the anal 3. Xenisma. 



£2 Scales small, with about 60 in the lateral line. ... 2. Planderus. 

 62 Dorsal fin small, with 7 to 10 rays; surface swimmers 4. Zygonectes. 

 d2 Teeth in a single series; dorsal fin in front of the anal . . 5. Lucania. 

 C2 Teeth not pointed but notched and tricuspid. 



di Dorsal fin with 10 to 12 rays 6. Cyprinodon. 



6.2 Dorsal fin with 15 to 18 rays 7. Jordanella. 



bo Anal fin of male a long sword-shaped organ; species vivipar- 

 ous {Pceciliida) i. Gamhusia. 



ao Lower jaw short; teeth movable; species mostly mud-eating. 



bi Teeth in a single series 2. Heterandria. 



bs Teeth in more than one series 3. Mollienisia. 



I. Fundulus Lacepede. Killifish. Body rather elongate, some- 

 times chubby; compressed behind; eyes large; teeth in 2 or more series 



Fig. 45. — Fundulus diaphanus (from Jordan cf Evermann) . 



in each jaw, and pointed; air bladder present: many species, mostly 

 American, living in fresh and brackish water and arms of the sea; 

 about 8 species in the United States. 



F. heteroditus (L.), Common killifish; mummichog. Length 75 to 

 150 mm.; head 3.5; depth 3.6; color of male greenish, sometimes orange 

 below; sides with many narrow, silvery bars made up of spots, besides 

 many scattered spots; median fins dark with pale spots; females plain; 

 dorsal fin 11 ; anal 10 or 11 ; scales 35 to 38-13 : Gulf of St. Lawrence to 

 Mexico; very common in shallow water along the sea shore and in the 

 mouths of streams. 



F. parvipinnis Girard. Length 100 mm.; head 3.5; depth 3.7; 

 dorsal fin with 13, anal with 11 rays; color light green, with about 20 



