CLUPEID^. 
145 
fin. Abdominal vertebrao about 23, caudals 13 to 15 in number. 
Paired fins small, the pelvic pair arising just behind the origin of 
the dorsal and midway between the pectorals and the anal; dorsal 
fin deeper than long, with about 12 rays, arising just before the 
hinder end of the anterior third of the back; anal fin not much 
extended, with 14 rays, arising far behind the dorsal, midway 
between the pelvic and caudal fins. Dorsal scutes narrow and 
longitudinally keeled, emarginate behind; ventral ridge-scales 20 to 
25 in number, not increasing in size backwards, smooth and serrated, 
but each produced at its hinder inferior angle into a long spine. 
Form. ^ Log. Eocene (Green Eiver Shales) : Wyoming. 
P. 6185-86. Two large specimens 0’18 in length. 
Purchased, 1890. 
49168. Specimen 0*13 in length. Purchased, 1878. 
P. 1859. Eine specimen 0’105 in length, displaying some of the 
head-bones and the ventral ridge-scales. Egerton Coll. 
P. 8393. Fractured specimen of the same size, with remains of the 
dorsal ridge-scales. Presented hy Walter Crouch, Esq., 1894. 
P. 4929. Well-preserved fish 0’09 in length. - 
Presented hy R. Lydelcker, Esq., 1885. 
49167. Imperfect smaller fish, showing scales. Pwrchased, 1878. 
P. 5527. Small well-preserved fish 0'055 in length, showing both 
the dorsal and ventral ridge-scales. Purchased, 1888. 
Diplomystus altus (Leidy). 
1873. Clupea alia, J. Leidy, Contrib. Ext. Vert. Fauna W. Territ. 
(Rep. U.S. Geol. Surv. Territ. vol. i. pt. i.), p. 196, pi. xvii. fig. 2. 
1877. Diplomystus altus, E. D. Cope, Bull. U.S. Geol. Surv. Territ. 
vol. hi. p. 811. 
1884. Diplomystus altus, E. D. Cope, Vert. Tertiary Form. West, 
Book I. (Rep. U.S. Geol. Surv. Territ. vol. hi.), p. 79, pi. ix. 
figs. 9-11, pi. X. fig. 5. 
Type. Nearly complete fish ; National Museum, Washington. 
A species almost identical with D. humilis, but exhibiting a 
deeper trunk, the maximum depth of the abdominal region slightly 
exceeding one third the total length of the fish to the base of the 
caudal fin. 
Form. Loc. Eocene (Green River Shales) : Wyoming. 
P. 4846. Imperfect fish 0*1 in length. Purchased, 1885. 
PAET IV. 
L 
