The Suckers 



None of the species has any rank as a game fish. They 

 rarely or never take a hook, except on set-lines. The methods 

 employed in their .capture are varied, but haul-seines, gill-nets, 

 pounds and other traps, and set-lines are the kinds of apparatus 

 in most general use. 



The habits of all the species ?re much the same. They are 

 all bottom feeders, feeding chiefly upon vegetation and the less 

 active and soft forms of smaller animal life such as worms, 

 larvae, and eggs of various kinds. 



They are all spring spawners, and nearly all have the habit 

 of running up stream at spawning time. Illinois is called the 

 "Sucker State" because its first settlers came up the river in 

 the spring when the suckers were running. 



Only the genera and species of some commercial importance 

 are considered at length. 



a. Dorsal fin long, with 24 to 30 rays; air-bladder in 2 



parts. 



b. Fontanelle present; body ovate; scales large. 



c. Mouth large, more or less terminal, protractile forward. Large 



species, dark in color ; Ictiobus, 38 



cc. Mouth small, inferior, protractile downward. Smaller species 



of pale coloration ; Carpiodes, 41 



bb. Fontanelle obliterated by the union of the parietal bones; 



body elongate ; " Cycleptus, 44 



aa. Dorsal fin short, with only 10 to 18 rays. 



d. Air bladder in two parts. 



e. Lateral line complete; scales small, 55 to 115 in lateral line. 



f. Fontanelle nearly or quite obliterated in adult; jaws with hard 



sheaths; posterior division of air bladder slender; Pantosteus, 45 

 ff. Fontanelle broad and evident at all stages of growth; posterior 

 division of air bladder broad. 



g. Nuchal region without a hump, the interneural spines normally 



developed. 



h. Mouth small, inferior, with thick papillose lips;. .Catostomus, 46 

 hh. Mouth very large, terminal, oblique; lips thin and nearly 



smooth. 



i. Gillrakers simple, fringe-like; Chasmistes, 54 



it. Gillrakers broad, shaped like the Greek letter ^ (delta), their 



edges entire and unarmed ; Deltistes, 57 



gg. Nuchal region with a high, sharp-edged hump;. .Xyrauchen, 57 

 ee. Lateral line interrupted or wanting; scales large, 40 to 50 in a 



longitudinal series. 



j. Lateral line entirely wanting; Erimy%on, 58 



;)'. Lateral line more or less developed, especially in adult; Minytrema, 59 



37 



