144 LIST OF FISH. 



single, circular, submarginal series, with a single, additional, odd 

 tooth in the centre above. Tongue with two conical, arched teeth. 

 Rich. Voy. Erebus $■ Terror, t. 38, cop. t. 1, f. 6. 



Mordacia, Gray, Proc. Zool. Soc. 1851. 



Petromyzon, sp., Rich. Voy. Erebus Sr Terror, t. 38, 1845. 



1. Mordacia mordax. Australian Lampern. 



Petromyzon mordax, Rich. Voy. Erebus $• Terror, t. 38, 1845. 

 Mordacia mordax, Gray, Proc. Zool. Soc. 1851. 



jj AB- — Tasmania. Mus. Haslar Hospital. 



Species of Doubtful Situation in the Tribe. 



1. Petromyzon appendix. Small Lamprey. 



Petromyzon appendix, De Kay, Nat. Hist, of New York, 381, pi. 



64, f. 211, pt. 1. Zool. 1842. 

 Hab. — N. America, Hudson River. 



" A ring of irregular shaped corneous processes within the oral 

 orifice and a large isolated double tooth of the same texture on the 

 inferior portion of the mouth." De Kay. 



2. Petromyzon tridentatus. Tridentate Lamprey. 



Petromyzon tridentatus, Gairdener, Rich. Faun. Bor. Amer. 293, 

 1836. De Kay, Nat. Hist, of New York, 381, pt. 1. Zool. 

 1842. 



H AB> — n. America. Falls of the Walamet. 



3. Petromyzon argenteus. Silvery Lamprey. 

 Petromyzon argenteus, Block, t. 415, f. 2. Schneid. Block, 532, t. 



102, f. 1, 1801. Skaw, Gen. Zool. x. pt. 2, p. 262, 1841. 

 Hab. — Indian Seas. 



4. Petromyzon bicolor. Brilliant Lamprey 



romyzon bicolor, i 

 romyzon niger, La 



Hab. — Europe, Seine 



Petromyzon bicolor, Shaw, Gen. Zool. v. pt. 2, p. 263, 1804. 

 Petromyzon niger, La Cepcde, iv. 667. 



