Zoological Society. 63 



series, diverging from the throat ; the inner ones large, and gra- 

 dually diminishing in size to the edge. Tongue with two very large, 

 long, curved teeth, with a triangular plate beneath at their base. 

 Dorsal fins two, far apart. Mouth moderate, edged with transverse 

 foUations. 



1. Velasia chilensis. Chilian Lampern. 



Hab. Chili. In fresh water. 



5. CARAGOLA. 



Upper inner teeth two, large, separate, lateral, submarginal, each 

 with three acute tubercles. Lower inner teeth large, crescent-shaped, 

 nine-lobed ; the central and two lateral lobes on each side larger. 

 The labial teeth in a subcircular, submarginal series, large, trans- 

 verse, band-like, with three or four tubercles. Tongue with two flat- 

 tened teeth, and a triangular, transverse plate below, with an acute 

 process between the teeth on the upper edge. Dorsal fins two, far 

 apart. 



1. Caragola lapicida. Caragol. 

 Hab. West Coast of America. 



6. MORDACIA. 



Upper inner teeth two, separate, lateral, subtrigonal, each with 

 three tubercles. The lower nine conical, acute, in an arched series ; 

 the five central smaller. Labial teeth small, conical, in a single, cir- 

 cular, submarginal series, with a single, additional, odd tooth in the 

 centre above. Tongue with two conical, arched teeth. (Rich. Voy. 

 Erebus & Terror, t. 38.) 



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



1. Mordacia mordax. Australian Lampern. 



Petromyson mordax. Rich. Voy. Erebus & Terror, t. 38, 1845. — 

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

 Hab. Tasmania. 



Species of Doubtful Situation in the Family. 



1. Petromyzon appendix. Small Lamprey. 



Petromyzon appendix, DeKay, Nat. Hist, of New York, 381. pi G4 

 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." — Be Kay. 



2. Petromyzon tridentatus. Tridentate Lamprey. 



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

 183G; De Kay, Nat. Hist, of New York, 381. pt. 1 ; Zool. 1842. 

 Hab. N. America, Falls of the Walamet. 



