298 
ACTINOPTERYOII. 
Genus TETRAGONOPTERUS, Cuvier. 
[Regne Animal, vol. ii. 1817, p. 166.] 
1 runk laterally compressed, but with rounded ventral bord ^ 
Anterior teeth stout and incisor-like, lateral teeth smaller , t 
of dentary and premaxilla laterally compressed and notchc i , ^ 
former in single and the latter in double series. Dorsal fin “ e ‘ 
and short-based ; anal fin more or less extended ; caudal fin ° r 
Scales of moderate size, not serrated ; lateral line conspicuous. 
Existing species in tho freshwaters of tropical America. 
Tetragonopterus avus, A. S. Woodward. 
[Plate XVII. fig. 1.] 
1898. Tetragonopterus avus, A. S. Woodward, Ilev. Mus. Paulista, v 
P- 66, fig. 3. 
Type. Imperfect fish ; British Museum. , 
A species attaining a length of ubout 0 - 2. Length of hca 
opercular apparatus about equal to maximum depth of trun , w ^ 
is contained slightly more than four times in the total lengt i ^ 
fish. Vertebras about 20 in the abdominal, 22 in the caudal 
Dorsal fin with 9, anal fin with about 22 rays, tho former 
pletely in advance of the latter. p.iulo, 
Form. Sf Loc. Tertiary Lignite : Taubate, Province of San 
Brazil. 
P. 9222. Type specimen, shown of nat. size in PI. XVII. fin- qq. 
Presented by John Gordon , Esq-, 
P. 9223-25. Twenty-five imperfect specimens, mostly larn e ^ 
the type. Presented by John Gordon, Esq-, 
P. 9013. Imperfect fish. By exchange, 1 
1898. 
Tetragonopterus ligniticus, A. S. Woodward. 
[Plate XVII. figs. 2, 3.] 
Tetragonopterus ligniticus, A. S. Woodward, loc. cit. p. 67, hg 
. 4 , 5 . 
Type. Imperfect fish ; British Museum. _ . , r0 . 
A smaller fish than the preceding, of comparatively s 0 c . lU (fal. 
portions. Vertebra, about 38 in total number, -0 ^ e | n ^ on( j the 
Pectoral fins relatively large, when ad pressed reaching e 5 , j reC tly 
origin of the small pelvic tins. Dorsal, fin with 8 or 9 rajs, 
