- 
416 White and Cope—The Green River Group. 
Ree ee PIS 8 to 0165 
ween er BUMS PRY OS el 022 
Beemtmer Beeb Oe BURL Min ee oc eee 0245 
Length of pectoral fin -..----_- Br ee Got. Poe ae 020 
meme Oh Verte! far! 2202 Ler Gl Fe PR ie 017 
arepen Of caudal peduncle 2... i... SL es 012 
Depth of head at orbil, ‘gedaialy wet ou SoU REG. ual 026 
The aia specimen of this fish is in excellent preserva- 
tion. The species is dedicated to Dr. C. A. White, the distin- 
euished Ba ADE and paleontologist. 
Plioplarchus sexspinosus Cope. 
This species is represented by two specimens, both of which 
lack the head and body anterior to the dorsal fin. One of the 
specimens is accompanied a. its reverse. The ata gyn Pe 
formula. shows more numerous spinous, ae less ‘enters 
ous span inten rays. The formula is ; O+17+4+; 
. VI-—9. The last anal radii are somewhat jancad and these 
may have been more than nine, but no trace of others exist 
and it is clear that they were less numerous than in P. Whitet 
There are about eighteen series of scales below the vertebral 
column at the front of fous dorsal fin. Their external surfaces 
are not so rough as in P. Whiter, as the granules are confined 8 
the center of the scale, and in the concentric lines are mu 
more obvious, and form a wider border. Ctenoid denticles ais 
tinct. Caudal fin openly emarginate 
Measurements : 
Depth at anterior edge of anal fin ..____......_-------- 0206" 
Length from do. to the end of the — vertebree _.---- 0305 
Length of caudal fin to vertebral centra _._.._.--------- 020 
Length of baie of doteal 8 (62 2 oe ee 0282 
Length of base of soft doteel 20 oe 2 eee 015 
Length of ae GP OMNI cE oe eo ye eis 017 
Length of base of spinousanal . 2... 25. 2-2 22h 008 
Length Of (i006 Gormal Wolds, 0 013 
Length of Siti sil apie te 015 
Depth of caudal peduncle, about ...........-.--------- oll 
Remarks :— 
Among the known extinct types of fishes it is Mioplosus 
Cope that approaches nearest this one. The former is charac- 
teristic of the Green River beds of the Lower Eocene. - e 
It only permits the general statement that its age may be 
tiary or Upper Cretaceous. 
