KEY TO THE COMMON SPECIES OF FISHES AND LAMPREYS 



1. Body snakc'like, long and cylindrical; scales never evident 2. 

 Body not snake-like; scaled or scaleless 11. 



2. Gills covered by the operculum; bony jaws present; ascending streams 



from the Atlantic; Family Anguillidae 



Angwlla rostrata (LeSueur) American Eel 

 Angiulla hostomensis (LeSueur) 

 (Anguilla chrysypa Raf.) 

 With several external gill openings; no operculum; mouth round, with' 

 out bony jaws; often parasitic on fishes; marine or fresh water; Family 

 Petromyzonidae Lampreys 3. 



3. Teeth evenly distributed in radiating series around the mouth opening 4. 

 Teeth placed in groups around the mouth opening 6. 



4. Dorsal fin in two separate portions; Atlantic states, ascending streams 



from the sea 



Petromyzon inarinns Linn. Sea Lamprey 



Dorsal fin continuous, although often deeply notched in the middle; 



central states (For revision of Genus Ichthyomyzon see Hubbs and 



Trautman, 1937, Univ. of Mich. Museum of Zoology Misc. Pub. 



No. 35) 5. 



5. Sucker around the mouth wider than the body, when expanded; para' 



sitic on fishes; Great Lakes and the Mississippi Valley 



Ichthyomyzon concolor (Kirtland) Silver Lamprey 

 Ichthyomyzon unicuspis Hubbs 

 (and related species) 

 Sucker around the mouth narrower than the body, when expanded; not 

 parasitic; Great Lakes region and the Mississippi Valley 

 Reighardina imicolor (De Kay) Lake Lamprey 

 Ichthyomyzon fossor R. 5? C. 

 (and related species) 



6. With a row of small teeth below the mouth opening, connecting the 



large lateral teeth (all within the ring of marginal teeth) ; dorsal fins 



separate 7. 



No row of small teeth connecting the lateral teeth below; dorsal fins 



separate or connected 9. 



7. With three large bicuspid teeth on each side of the mouth opening; 



northeastern and north'Central states 



Lethenteron appendix (De Kay) Eastern Brook Lamprey 

 Entosphenus lamottenii (LeSueur) 

 (Lampetra wilderi Gage) 

 With four large teeth on each side of the mouth, the first and last bicus' 

 pid, the middle two tricuspid; ascending streams from the Pacific 8. 



8. With 57 to 67 muscle segments from the gills to the anus; color greenish; 



California 



Entosphenus ciUatus (Ayres) Green Lamprey 

 With 68 to 74 muscle segments from the gills to the anus; color brown' 

 ish; West Coast 



Entosphenus trideyitatus (Gairdner) Western Lamprey 



258 



