Usually with about twenty dark bars on each side; east of the Alleghen' 

 ies (Possibly a variation of E. vermiculatus) 



Esox americanus Gmclin Barred Pickerel 



89. Upper lip protractile, separated from the forehead by a distinct groove 



Top-minnows and Killifishes 90. 



Not so Mud-minnows 112. 



90. Pelvic fins usually absent; desert species of the southwest 91. 

 Pelvic fins usually present 93. 



91. Sides of female with obscure dark bars; males blue; depth of body almost 



one-half the length; jaw teeth with three points 



Cyprinodon nevadensis Eigenmann (of Family Cyprinodontidae) 



Sides blotched or mottled; body less deep; jaw teeth conical or with two 



points 92. 



92. Sides dark mottled; jaw teeth conical; Family Empetrichthyidae 



Empetrichthys merriami Gilbert Death Valley Minnow 

 Sides v.'ith dark blotches arranged in lengthwise rows; jaw teeth with 

 two points 



Cyprinodon haileyi Gilbert (of Family Cy prinodontidae) 

 Crenichthys haileyi (Gilbert ) 



93. Anal fin of male long and sword-shaped; body of female enlarged 



through the region of the abdomen; viviparous species; Family 



Poeciliidae 94. 



Anal fin normal; abdomen more compressed; not viviparous; Family Cy- 



prinodontidae 97. 



94. Dorsal fin with about fifteen or sixteen rays; anal fin of female with 



about eight rays; southern states to Texas 



Mollienesia latipinna LeSueur Mudfish, Mollie 

 Dorsal fin with about seven to nine rays; anal fin of female with about 

 six to ten rays 95. 



95. Dorsal fin starting above or before the beginning of the anal fin; Colora- 



do River basin 



Poeciliopsis occidentalis (B. £«? G.) 

 Dorsal fin more posterior than the anal fin 96. 



96. Lower jaw weak; teeth movable; southern states 



Heterandna formosa Agassis Top-minnow 

 Lower jaw projecting; teeth slightly movable; southern Atlantic and 

 Gulf coasts and lower Mississippi Valley 



Gamhusia patruelis (B. & G.) Viviparous Top-minnow 

 Caynhusia affinis (B. 6? G.) 



97. Dorsal fin more posterior than the anal fin, with eleven or less rays 98. 

 Dorsal fin usually starting above or before the beginning of the anal fin, 



with nine or more rays 102. 



98. Dorsal fin with nine or ten rays; sides plain colored or each with a dark 



lengthwise band 99. 



Dorsal fin with seven or eight rays; sides barred or striped or with length- 

 wise rows of dark spots 100. 



269 



