140 
ACTINOPIEEYGir. 
Each pectoral fin with about 12 rays, the longest not reaching the 
pelvic pair, which arises nearly midway between the pectorals and 
the anal, just in advance of the origin of the dorsal; dorsal fin 
deeper than long, with 11 or 12 rays, arisiug at the hinder end of 
the anterior third of the back ; anal fin much extended, with 40 
rays. Dorsal scutes about twice as broad as long, finely denticu¬ 
lated on the posterior border, and nearly 40 in number; ventral 
ridge-scales about 25 in number, not serrated, decreasing in size 
backwards. 
The so-called Diplomystus theta (Cope, Joe. cit. 1877, p. 811, and 
Jog. cit. 1884, p, 77; Clupea theta, Cope, Bull. U.S, Geol. Surv. 
Territ. no. 2, 1874, p. 51), founded on an imperfect specimen, may 
also belong to this species. Diplomystus ]jectorosus (Qo'^q,Ioc. cit. 
1877, p. 810, and loc. cit. 1884, p. 76, pi. x. fig. 3) is also scarcely 
distinct. 
Form. Log. Eocene (Green lliver Shales) : lYyoming. 
P. 5230. Eine specimen 0-46 in length, displaying the median fins 
and remains of the paired fins ; found 10 miles from 
Sillein, on the Oregon short line of railway, Wyoming. 
The jaws are crushed slightly forwards, the hyoid arch a 
little downwards; the axial skeleton of the trunk is very 
well shown. Presented J)y Samuel Lalng. Esq., 1887. 
P. 7489-90. Two similar specimens, showing patches of minute 
stout conical teeth on some of the inner bones of the 
mouth. Purchased, 1895. 
P. 5218. Smaller fish 0-27 in length. 
Presented hy Lord AveJniry, 1886. 
P. 1860. Imperfect specimen 0-18 in length ; labelled “ Bear Biver, 
Idaho,” biU probably from the Green Biver Shales of 
Wyoming. Egerton Coll. 
P. 4928. Still smaller specimen displaying the ridge-scales. 
Presented hy R. Lydehker, Esq., 1885. 
49166. Small fish about 0*105 in length. Purchased, 1878 
Diplomystus brevissimus (Blainville). 
1818. Cluqjecubrevissimus, H. D. de Blainville, Nouv. Diet. d’Hist. Nat. 
vol. xxvii. p. 364. 
1839-44. Clupea brevissvma. L. Agassiz, Poiss. Foss. vol. v. pt.ii. p. 117, 
pi. Ixi. figs. 6-9. 
1850. Clupea brevissima, F. J. Pictet, Poiss. Foss. Mt. Liban, p. 41, 
pi. viii. figs. 1, 2. 
