COPE ON ICHTHYIC FAUNA OF THE GREEN RIVER SHALES. 811 
dorsal scuta are furnished in the D. pectorosus with an especially. 
prominent median keel. 
Measurements. 
: M. 
Total length... 2.2... Gah dicahwictaahslaSjay spar oaraiah adi ahara rial, aatote ereye era eiarasiche tect ages 0.060 
Length (axial) to below D. Lo... ce. cece ce cen e eee ce ne ne seen cee eee ceceee cece 0,088 
Length (axial) to above A. T.sccee sane ce secs toes ce sacnse veceee se tecd cece eee 00043 
Length (axial) to base of caudal fin .. 2.0... 202. cee cee eee cee emcee eee cee eee 0.070 | 
Meng tli Of Noad se ee. ghce sue Geeieneew cveckeels Gteeeteowocecn basseces vabicanere 0.022 
Deptliat Ori hi gastece oscuweeewekets aber ose wen ceded Sesesewess cece SOUL 
Depth at pectoral fin..........222..02.. a oie Sica 2S chai eiil oe alee etrae Soetae eee 0.026 
Depth at dorsal fin.............-.- ert SRE R Dt eases emer Gmenssents 0.024 
Depth at caudal peduncle ..... 22... caes cece teccee cocene coceee coe saceccuees 0.008 
- This species is represented by several specimens. 
DIPLOMYSTUS HUMILIS, Leidy. 
Clupea humilis, Leidy, Final Report U. 8. Geol. Surv. Terr. i, p. 195, pl. xvii, 
fig. 1. 
This and the following species, already referred to a distinct section 
of the genus Diplomystus, differ from those above described in several 
points. They have a much shorter anal fin, and the caudal part of the 
vertebral column is thus shorter. The anterior neural spines do no pre- 
sent the antero-posterior laminar expansion. The ventral fin commences 
alittle behind the origin of thedorsal. The formule for the D. humilis are 
as follows :—Radii: D.I—11; A.I—14. Vertebre: D.21; 0.13. Depth 
to length as 3: 8.5. The Diplomystus theta (Clupea theta Cope, Ann. 
Rep. U. 8. Geol. Surv. Terr. 1873, p. 461) is intermediate between the 
species of the two sections in the structure of its anal fin, which includes 
twenty-six rays. 
As at the Green River locality, so at this one, this Herring is the most 
abundant species. One-third the entire number of specimens are refer- 
able to it. 
DIPLOMYSTUS ALTUS, Leidy. 
Clupea alta, Leidy, loc. cit. p. 196, pl. xvii, fig. 2. 
Also abundant. Formule :—Radii: D. 1.11;, A. 1. 13-15. Vertebre: 
D. 22; C.12. Depth to length (without caudal fin) as 4:8. 
ERISMATOPTERUS ENDLICHI, sp. nov. 
This fish displays the characters of the genus to which it is referred, 
and of which a description will be found in the Annual Report of the 
United States Geological Survey of the Terri tories for 1870, p. 427. The 
ventral fins are neither abdominal nor pectoral, but intermediate, and the 
dorsal fin is above the abdomen. Both it and the anal are short, and 
are supported in front by two or three strong appressed spines. The 
vertebree are hourglass-shaped, and the scales cycloid. The ventral 
rays are seven in num ber in #. endlichi and LE. rickseckeri. 
