PEECID^. 
517 
decreasing in length; posterior dorsal relatively low, with 
short spine and 8 articulated rays ; anal with 3 short 
spines and 7 articulated rays; eaudal fin forked. Scales 
very small. Egerton ^ Enniskillen Colls. 
P. 3912. Nearly similar Percoid 0'105 in length, with 11 articulated 
rays in posterior dorsal and 8 articulated rays in anal 
fin, and caudal fin rounded; Lower Oligocene, Aix-en- 
Provence. Enniskillen Coll. 
Genus MIOPLOSUS, Cope. 
[Bull. U.S. Geol. Surv. Territ. vol. hi. 1877, p. 813.] 
Trunk laterally compressed and elongate-fusiform. Articulation 
of mandible beneath hinder border of orbit, and all teeth very 
small; ascending limb of preoperculum smooth, lower limb coarsely 
serrated; operculum rounded, without spines. Yertebrac 10 or 11 
in abdominal, 14 or 15 in caudal region. Two dorsal fins, the 
anterior with 9 spines, the posterior with 1 spine and 12 to 14 
articulated rays; anal fin with 2 spines and 10 to 14 articulated 
rays ; caudal fin slightly forked. Scales finely serrated. 
An extinct North-American freshwater Eocene genus. 
Mioplosus labracoides, Cope. 
1877. Mioplosus labracoides, E. D. Cope, Bull. U.S. Geol. Surv. Territ. 
vol. hi. p. 814. 
1884. Mioplosus labracoides, E. D. Cope, Yert. Tert. Form. West, 
Book I. (Hep. U.S. Geol. Surv. Territ. vol. hi.), p. 89, pi. xii. 
%. 1 . 
'k'ype. Nearly complete fish; National Museum, Y ashington. 
The type species, attaining a length of about 0*35. Maximum depth 
of trunk about equalling length of head with opercular apparatus, 
and contained four times in total length of fish. Third dorsal fin- 
spine longest; 12 articulated rays in dorsal, 14 in anal fin. 
Fo'i^i. ^ Log. Eocene (Green Biver Shales) : Y^yoming, U.S. A. 
P. 5217. Slightly distorted specimen 0*25 in length. 
Presented by Lord Avebury, 1886. 
P. 7492. Larger, more distorted specimen. Purchased, 1895. 
« 
The following species, all except the fourth from the Green Eiver 
Shales of Wyoming, have also been distinguished, but only differ 
very slightly from the type species :— 
