SYSTEMATIC SYNOPSIS OF FOSSIL BIBBS. 
827 
Ichfhyornis aud Archceopteryx, shows greater diversity from one another than that existing 
among all known birds of later geologic and of the present epoch. 
The first remains of this now famous species were found by Prof. Marsh in November, 
1870, in the yellow chalk of the Pteranodon beds, near the Smoky Hill river in Kansas. The 
type spocimen was fouud in July, 1871, on the south bank of the same river, about twenty 
miles east of Fort Wallace, imbedded in gray calcareous shale. Many other remains have 
also been, collected, representing in all some forty different individuals, all from the same 
geologic horizon in Western Kansas, and most of them near the locality of the original ones. 
They are all preserved in the Museum of Yale College. 
31. HESPERORNIS CRASSIPES. 
Lestornis crassipes, Marsh, Am. Joum. Sci., xi, June, 1876, p. 509. 
Hesperornis crassipes, Marsh, Odont., 1880, p. 196, figg. 40 a-d. pll. vii, xvii. 
Based upon a nearly complete skeleton from the yellow chalk of Western Kansas, indicat- 
ing a bird considerably larger than H. regalis, and one that may prove to be generically 
distinct. Deposited in the Yale Museum. 
32. HESPERORNIS GRACILIS. 
Hesperornis gracilis, Marsh, Am. Journ. Sci., xi, June, 1876, p. 510. — Id., Odont., 18S0, 
pp. 99, 197. 
A third species, from the same horizon and locality, represented by two specimens, one of 
them a nearly complete skeleton. Deposited in the Yale Museum. 
03. ICHTHYORNIS DISPAR. 
Iclithyornis dispar, Marsh, Am. Journ. Sci., iv, Oct., 1872, p. 344. — Id., ihid., v, Feb., 
1873, p. 161. — Id., iUd., Mar., 1873, p. 230. — Coues, Key, 1872, p. 350. — Owen, Journ. 
Geol. Soc. Lond., xxxix, 1873, p. 520.— Woodw., Pop. Sci. Rev., Oct., 1875, p. 348. — Marsh, 
Am. Nat., ix, Dec, 1875, p. 625. — Id., Geol. Mag., iii, 1876, p. 49. — Huxl., Pop. Sci. 
Monthly, X, 1876, pp. 215-218. —Marsh, Journ. de Zool., iv, 1875, p. 494, pi. xv; vi, 1877, 
p. 385. — Id., Odont., 1880, pp. 119-183, 197, pll. xxi-xxvi. 
This remarkable bird, forming a type of the whole group Odontotormce (p. 237) of Odont- 
ornithes, with general characters of the skeleton like those of ordinary birds, yet with socketed 
teeth and biconcave vertebrae, was discovered in 1872 near the Solomon river in Northwestern 
Kansas, in the Pteranodon beds of the middle Cretaceous. It was about as large as a pigeon. 
The remains of about nine individuals, all from the same region, are preserved in the Museum 
at Yale College. 
34. ICHTHYORNIS AGILIS. 
Graculavus agilis, Marsh, Am. Joum. Sci., v, Mar., 1873, p. 230. 
Ichthyornis agilis, Marsh, Odont., 1880, p. 197. 
From the same horizon in Western Kansas, on Butte Creek, a tributary of the Smoky 
Hill river, where discovered in October, 1872. The remains are preserved in the Yale College 
Museum. 
35. ICHTHYORNIS ANCEPS. 
Graculavus anceps, Marsh, Am. Journ. Sci., iii. May, 1872, p. 364. — Coues, Key, 
1872, p. 350. — Marsh, Am. Journ. Sci., v. Mar., 1873, p. 229. — Id., Odont., 1880, pp. 
124, 198. 
Kesembling I. dispar, but with slenderer jaws and more teeth. The right lower jaw of 
the type specimen of I. dispar shows twenty-one distinct sockets. Discovered in November, 
1870, in the gray shale of the middle Cretaceous, on the north fork of the Smoky Hill river in 
western Kansas, where other specimens have since been found. All are preserved at Yale. 
36. ICHTHYORNIS LENTUS. 
Graculavus lentus, Marsh, Am. Joum. Sci., xiv, Sept., 1877, p. 253. 
Ichthyornis lentus, Marsh, Odont., 1880, p. 198. 
