10 



FISHES OF ILLINOIS 



Supraorals. 

 bicuspid . . 



unicuspid. . . 

 tricuspid. . . 



quadricuspid 



Dorsal fin continuous with caudal, with a perceptible depression in front 

 of vent; greatest height of fin about % distance from vent to end of tail, 

 height at depression about % greatest height anterior to it, and about y% 

 to % height of posterior portion; the larvse with the dorsal fin single as in 

 adults. 



Our 15 collections of this species are chiefly from the Illinois 

 River at Havana, Meredosia, Ottawa, and Pekin. We have 

 also 1 collection from Green River, 1 from the Wabash at Mt. 

 Carmel, and several specimens from the Mississippi at Alton, 

 and have records of the occurrence of the species at Galena, 

 Cairo, and Quincy. It seems that lampreys are, on the whole, 

 rather rare in our waters. Illinois River fishermen seem to know 

 little of them. Fishes with lampreys attached, or with marks 

 of their previous presence, are not common in the seine catches 

 along the Illinois. At Alton they seem to be more numerous, 

 showing their usual preference for spoonbills, which species is 

 said rarely to be taken at Alton or Grafton without lamprey 

 marks. At Havana also they are commonest on the spoonbills 

 sometimes two or three fast to a single fish and next on 

 buffalo-fish and carp. 



At Galena and at Cairo lampreys have been seen by one of 

 the State Laboratory assistants, Mr. J. E. Hallinen, attached 

 to large catfish. We may consequently say that, so far as known 

 to us, lampreys are not seriously injurious to the fisheries or 

 the fish population of this state, perhaps because of the scarcity 

 of suitable nesting places in our comparatively sluggish and 

 muddy streams. 



This species is found in the Great Lakes and the St. Law- 

 rence River, in the valleys of the Ohio, the Missouri, and the 

 upper Mississippi, and northward to the Assiniboin (castaneus). 



