Dorosoma cepedianum (LeSueur) Gizzard Shad 

 Dorsal fin not so; Family Clupeidae Herrings 118. 



118. Toothless; upper jaw appearing notched at tip 119. 

 With weak teeth; upper jaw not notched 120. 



119. With one or more small dark spots behind the operculum; ascending 



streams from the Atlantic; introduced on the Pacific slope 

 Alosa sapidissima (Wilson) Common Shad 

 Without such spots; Ohio River, Mississippi Valley 

 Alosa ohiensis Evermann Ohio Shad 



120. With a small black spot behind the operculum; Atlantic states 



Poynolohus pseudoharengus (Wilson) Alewife 

 No such spot; Mississippi Valley and Gulf 



Pomolohus chrysochloris Raf. Skipjack, Blue Herring 



121. Dorsal fin with more than ten rays (rarely as few as nine) or else with 



the lips thick, wrinkled, and covered with minute projections; with 

 numerous pharyngeal teeth in a comb'like series; Family Catostomidae 

 Suckers 122. 



Dorsal fin with not more than ten rays; lips usually thinner; edge of 

 upper jaw formed by the premaxillaries alone; with less than ten teeth 

 on each pharyngeal bar; Family Cyprinidae Minnows 157. 



122. Dorsal fin long, with twentythree to forty rays 123. 

 Dorsal fin shorter, with nine to twenty rays 130. 



123. Scales small, about fifty-six in the lateral line; eye behind middle of 



head; Mississippi Valley 



Cycleptus elongatus (LeSueur) Blackhorse, Missouri Sucker 

 Scales larger, not over forty-five in the lateral line; eye before middle of 

 head 124. 



124. Longest ray of dorsal fin usually shorter than one-half the base of the 



dorsal fin; anterior fontanelle (on front of skull) reduced or absent; 



Mississippi Valley 125. 



Longest ray of dorsal fin usually one-half or more as long as the base of 



the fin; with a well developed anterior fontanelle 127. 



125. Mouth terminal, very oblique, about on a level with the lower margin 



of the eye; gill rakers on first arch, counted from posterior face, almost 

 100 



Megastomatohus cyprinella (C. & V.) Common Buffalo 

 Mouth subterminal to inferior, less oblique; upper lip below the level of 

 the lower margin of the eye; gill rakers so situated less than 60 126. 



126. Back with a high elevation; depth of body more than one-third the length 



Ictiohus huhalus (Raf.) Small-mouth or Razor-back Buffalo 

 Back only slightly elevated; depth of body about one-third the length 

 (Not clearly distinct from the preceding species) 



Ictiohus urns (Agassiz) Mongrel or Black Buffalo 

 Ictiohus niger (Raf.) 



127. Longest ray of dorsal fin almost as long as the base of the fin; about a foot 



long 128. 



272 



