62 Zoological Society. 



2. Lampetra planeri. Fringed-lipped Lampern. 



Petromyson planeri, Linn. Bloch, viii. pi. 78. f. 3 ; Linn. (edit, de 

 Gmelin) ; Schneid. Bloch, 531, 532, 4, 1801 ; Shaw, Gen. Zool. v. 

 pt. 2. p. 259, 1804 ; Jen. Man. Brit. Vert. 522. sp. 21 1, 1835 ; Mull. 

 Mem. de I'Acad. Berlin, 78, 1834; Cuv. Reg. An. ii. 404, 1829; 

 Yarr. Brit. Fish. 2 ed. ii. 607, 1841. — Lmnproiea planer, Bonn. 

 Planches de I'Encycl. Meth. — Le Petromyzon planer, Lacepede, 

 Hist. Nat. des Poiss. i. 30. pi. 3, 1798. 



Hab. Europe. 



** Dorsal fin in contact with the second. 



3. Lampetra sanguisuga. Leech Lampern. 



Petromyzon Sanguisuga, Lacepede, Hist. Nat. des Poiss. ii. 99. 

 pi. 1 ; Supp. to Petromyzon ; Shaw, Gen. Zool. v. pt. 2. p. 261, 1804. 

 — Petromyzon planeri, var., Cuv. Reg. An. ii. 118. 



Hab. Europe, Seine. 



A very doubtful species ; Cuvier says it is the same as the former. 



4. Lampetra Lamottenii. American Lampern. 



Petromyzon Lamottenii, Lesueur, Hist. N. A. ; De Kay, Nat. Hist, 

 of New York, 382. pi. 79. f. 249 (mouth), pt. 1 ; Zool. 1842. 

 Hab. N. America, New York. 



3. GEOTRIA, n. g. 



Upper internal tooth large, transverse, crescent-like, divided into 

 four lobes ; the two inner lobes small, acute ; outer truncated. The 

 lower internal tooth transverse, narrow, slightly sinuous. The labial 

 teeth numerous, far apart, conical, acute, in arched series, diverging 

 from the throat; the innermost one larger, rest small; the inner- 

 most one of the lower part on each side small, elongate, transverse, 

 with two small, rudimentary tubercles. Tongue with two elongate, 

 conical, arched teeth, with a triangular plate on the lower side of the 

 base. Throat with a very large dilatable pouch. Dorsal fins two, 

 far apart. Mouth very large, surrounded with rather large, trans- 

 verse, torn leaves. 



This genus chiefly differs from Velasia in the rudimentary state 

 of the lower internal tooth, in the form of the labial teeth, in the 

 large size of the oral disk, and the extraordinary development of the 

 throat-pouch, which is found in a rudimentary state in the Petro- 

 myzon marinus. This development of the pouch is perhaps to adapt 

 the animal to the long drought of the Australian rivers. 



1. Geotria australis. Pouched Lamprey. 

 Hab, South Australia. Fresh water. 



4. VELASIA. 



Upper internal teeth large, transverse, crescent-like, divided into 

 four flat, elongated lobes ; the outer lobes largest. The lower inter- 

 nal teeth large, transverse, crescent-like, convex, denticulated on tlie 

 edge. The labial teeth very numerous, truncated, in crowded, arched 



