10 FISHES OF ILLINOIS 



instances of as many as 6 or 7 biscupid extraorals having been noted in 

 specimens with bicuspid supraorals.* 



Supraorals Infraorals. Extraorals. Specimens. 



bicuspid 7 all unicuspid [concolor) 5 



7 1-7 bicuspid 5 



S " 3 



8 2-7 " 6 



9 •' 4 



9 6 " 1 



10 2 1 



unicuspid 7 " 1 



tricuspid S 1 



s 3 iS ri 



" 9 3 gf 1 



10 6 u 3 [ 1 



quadricuspid 13 S 1 



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 abotit f greatest height anterior to it, and 

 about \ to § height of posterior portion; the larva- 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 Ouincy. 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 com- 

 monest on the spoonbills — sometimes two or three fast to a single 

 fish — and next on buffalo-fish and car]'. 



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

 Slate Laboratory assistants, .Mr. J. E. Hallinen, attached to large 



fish. We may consequently say that, so far as known to us, 

 lampreys arc not seriously injurious t< > the fisheries or t lie fish pi ipu 

 lation of this state, perhaps because of the scarcity of suitable 

 nesting places in our comparatively sluggish and muddy streams. 



Tins species is found in the Greal Lakes and the St. Lawrence 

 River, in the valleys of the Ohio, the Missouri, and the upper Mis 

 sissippi, ami northward to the Assiniboin (castaneus). 



* A study of oui ' I is of Ichthyom yzon sho i i ; un1 of niter I 



in dental charactei tha impossible the separation of the nominal 



dor), as is evidenl from the following tabulation: 



