FISHES OF THE EAST COAST OF NORTH AMERICA. 13 



Class C— MARSIPOBRANCHIL 

 Order 11. — Hyperoartia. 



Sub-order. 



Super family. 



Family. 



Petromyzontidae. . (106) 



Sub-family. 



PetromyzontinaB. 



Geuus. 



Petromyzon (Linn.) Gray. 



Ammoccetes (Dum.) Gill. 



Order 12. — Hyperotreta. 



Myxinidae (107) Myxiue Linn. 



Class D.— LEPTOCARDII. 

 Order 13. — Cirrostomi. 



Eianchiostomidas . (108) Brancbiostoma Costa 



