514 
ACTINOPTERYGII. 
Genus PERCICHTHYS, Girard. 
[Proc. Acad. Nat. Sci. Philad. 1854, p. 197.] 
Head and trunk laterally compressed. Mouth protractile, with 
minute teeth on premaxilla, dentary, vomer, and palatine ; supra- 
maxilla present. Prcoperculum with serrations, those on lower 
limb antrorse ; operculum with one spine behind ; six or seven 
branchiostegal rays. Vertebrae 14 or 15 in the abdominal, 18 to 20 
in the caudal region. Two dorsal fins, the anterior with 8 to 1 1 
spines, the posterior with 1 or 2 spines and 10 to 13 articulated 
rays ; anal tin with 3 spines and 8 to 1 0 articulated rays ; caudal 
tin truncate or slightly forked. Lateral line complete. 
A South-American freshwater genus found in Chili and 
Argentina. 
Percichthys antiquus, A. S. Woodward. 
1898. Percichthys antiquus, A. S. Woodward, Rev. Mus. Paulista, vol. 
iii. p. 08, tigs. 6,7. 
Type. Imperfect fish ; Senekenbcrg Museum, Frankfurt. 
A species attaining a length of about 0T2. Maximum depth of 
trunk about equalling length of head with opercular apparatus, 
which is contained three and a half times in total length of 
Dorsal fins with 11 spines and 9 or 10 articulated rays; anal fin 
with 3 spines and 8 or 9 articulated rays. 
Form. S[ Loc. Tertiary Lignite : Taubate, Province of San Taulo, 
Brazil. , 
P. 9011. Dorsal portion of trunk, described and figured, loc. at. 
p. 08, fig. 7. By exchange, 1S98. 
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. Vertebral 10 to 12 in the abdominal, 10 to ‘ n 
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. 
