554 ACTINOPTERTGII. 
Family CHROMID^. 
Narial opening single on each side, and scales usually ctenoid, 
otherwise as Labridag. 
Tropical and subtropical freshwater fishes, very numerous and 
varied in the existing fauna but scarcely known among fossils. 
Only one extinct genus is recognised. 
Genus PRISCACARA, Cope. 
[Bull. U.S. Geol. Surv. Territ. vol. iii. 1877, p. 816.] 
Teeth on margin of jaws minute and simply conical; similar 
teeth on vomer; upper and lower pharyngeal bones closely studded 
with short, sessile, conical teeth. Preoperculum serrated ; apparently 
'J 
/S~ 
\A*. 
eight branchiostegal rays. Spinous portion of dorsal fin more 
extended than soft portion ; anal fin with three spines; caudal fin 
rounded. Scales ctenoid, and lateral line conspicuous. 
An Eocene American freshwater genus, differing from all existing 
genera (according to Cope) in the possession of vomerine teeth. 
Priscacara serrata, Cope. 
1877. Priscacara serrata, E. D, Cope, Bull. U.S. Geol. Surv. Territ. 
vol. iii. p. 816. 
1884. Priscacara serrata, B. Cope, Vert. Tert. Form. West, Book. 1. 
(Rep. U.S. Geol. Surv. Territ. vol. iii.), p. 93, pi. xiii. fig. 1. 
Type. Imperfect fish; National Museum, Washington. 
The type species, attaining a length of about 0*25. Length of 
head with opercular apparatus contained about three times, maxi¬ 
mum depth of trunk about twice in total length of fish to base of 
caudal fin. Vertebrae 9 in the abdominal, 14 in the caudal region. 
Dorsal fin with 10 spines and 11 or 12 articulated rays, anal with 
3 spines and 10 articulated rays. 
Form. Sf Loc. Eocene (Green River Shales): Twin Creek, 
Wyoming, U.S.A. 
P. 5927, P. 6022. Two good specimens. 
Presented hy T. A. Rickard, Esq., 1889. 
P. 1915. Imperfect fish, probably of this species. Eyerton Coll. 
Priscacara clivosa. Cope. 
18/8. Priscacara E. D. Cope, Bull. U.S. Geol. Surv. Territ.# 
vol. iv. p. 76. 
