514 
ACTINOPTERYGII. 
Genus PERCICHTHYS, Girard. 
[Proc. Acad. N’at. Sci. Philad. 1854, p. 197.] 
Head and trunk laterally compressed. Houth protractile, with 
minute teeth on premaxilla, dentary, vomer, and palatine; supra- 
maxilla present. Preoperculum with serrations, those on lower 
limb antrorse; operculum with one spine behind; six or seven 
hranchiostegal rays. Vertebrae 14 or 15 in the abdominal, 18 to'20 
in the caudal region. Two dorsal fins, the anterior with 8 to 11 
spines, the posterior with 1 or 2 spines and 10 to 13 articulated 
rays; anal fin with 3 spines and 8 to 10 articulated rays ; caudal 
fin truncate or slightly forked. Lateral line complete. 
A South-American freshwater genus found in Ghili and 
Argentina. 
Perciehthys antiquus^ A. S. Woodward., 
1898. Percichthys antiquus, A. S. Woodward, Rev. Mus. Paulista, vol. 
iii. p. 68, figs. 6,7. 
Type. Imperfect fish ; Senckenherg Museum, Prankfurt. 
A species attaining a. length of about 0*12. Maximum depth of 
trunk about equalling length of head with opercular apparatus, 
which is contained three and a half times in total length of fish. 
Dorsal fins with 11 spines and 9 or 10 articulated rays; anal fin 
with 3 spines and 8 or 9 articulated rays. 
Form. 4 * Log. Tertiary Lignite : Taubate,. Province of San Paulo, 
Brazil. 
P. 9011. Dorsal portion of trunk, described and figured, loc. ciU 
p., 68, fig. 7. By exchange, 1898. 
Genus PROPERCA, Sauvage. 
[Bull. Soc. Geol. France (3) vol. viii. (1880), p. 452.] 
Head and trunk laterally compressed. Mouth large, and all 
teeth minute. Preoperculum gently rounded and serrated, without 
spine at angle. Vertebrae 10 to 12 in the abdominal, 16 to 18 in 
the caudal region. Anterior dorsal fin more extended than the 
posterior dorsal, the two probably connected at the base; anterior 
dorsal with 9 spines, posterior dorsal with 1 spine and 9 to 12 arti¬ 
culated rays; anal fin small, with 3-spines and 8 to 10'articulated 
rays; caudal fin forked. Scales large or of moderate size, finely 
denticulated. 
