802 FISHES — CATOSTOMID^. 



Artifical Key to the Families of Tkleocephali found in Ohio. 



"Ventral fins present, abdominal. 

 t Rayed dorsal fin single ; no spines. 

 a. Adipose fin present. 



J. Scales ctenoid ; lateral margins of npper jaw formed by pre-maxillaries alone. 



Pbrcopsid^. 14. 

 ii. Scales cycloid ; lateral margins of npper jaw formed by maxillaries. 



Salmonid^. 13. 

 aa. Adipose fin wanting. 



c. Abdomen compressed to a sharp edge, which is armed with hard plates or 

 serratures. 

 d Month small, the npper jaw the longer; maxillary simple. 



DoROSOMATiD.a:. 1(0. 

 dd. Mouth rather large, the jaws about equal; maxillary in three parts, 



Cldpeid^. 11. 

 CO. Abdomen not serrated, 

 e. Jaws toothless ; pharyngeals falciform. 

 /. Dorsal rays 11 or more ; pharyngeal teeth very numerous in a single row. 



CATOSTOMIDiE 8. 



fj. Dorsal rays 7 to 9 ; pharyngeal teeth few Cyprinid^. 9. 



ee. Jaws with teeth. 

 g. Vent normal, behind the ventrals; eyes developed. 

 A. Head naked ; teeth strong ; scales large, silvery. Hyodontid,e. 12. 

 hh. Head scaly more or less ; dorsal fin inserted posteriorly, opposite anal or 

 nearly so. 

 i. Upper jaw not protractile. 

 j. Jaws very long, armed with strong unequal, movable teeth. 



EsociD^. 18. 

 jj. Jaws short, armed with bands of small teeth. , UMBRiDiE. 17. 

 ii. Upper jaw extremely protractile ; head flattened above ; mouth small ; 



caudal rounded CYPMNODONTiDa;. 16. 



gg. Vent jugular, before the ventiral fins ; eyes concealed. 



Amblyopsid^. 15. 

 1 1 Rayed dorsal fins two, the a^iterior of a few feeble spines ; body elongate, with a 



silvery lateral band Atherinidje. 19. 



**Ventral fins present, thoracic or jagular. 

 a. Skin covered with scales. 



6. Anterior three or more rays of dorsal fin spinous ; ventrals thoracic. 

 0. Dorsal with more than five spines. 

 d. Vomer with teeth, 

 e, Branchiostegal 7 ; dorsal fins two ; preopercle wanting. 



Pekcid^. 24. 

 ee. Branchiostegals 6 ; preopercle nearly or quite entire. 

 /. Anal spines one or two ; dorsal fins two. . Ethbostomatid^. 23. 

 ff. Anal spines three to nine ; dorsal fin continuous. 



Centrakchid^. 22. 

 dd . Vomer toothless ; anal spines two. 

 g. Second anal spine not larger than first. . . ETHEOSTOMATlDiE 23. 



