826 
SYSTEMATIC SYNOPSIS OF FOSSIL BIRDS. 
impossible to say as yet whether or not they are odontornithic. All the deposits of Cretaceous 
age in North America, in which birds have been found, are marine, and the species appear to 
have all been aquatic. 
26. APATORNIS CELER. 
Ichthyornis celer, Marsh, Am. Joum. Sci., v, Jan., 1873, p. 74. 
Apatornis celer, Marsh, Am. Joura. Sci., v, Feb., 1873, p. 162. — Id., ibid., v, Mar., 
1873, p. 230. — Id., ibid., x, Nov., 1875, p. 404. — Id., Am. Nat., ix, Dec, 1875, p. 626.— 
Id., Geol. Mag., iii, Feb., 187G, p. 50. — Woodw., Pop. Sci. Rev., Oct., 1875, p. 349.— 
Marsh, Odont., 1880, p. 192, pll. xxviii-xxxiii. 
A bird about the size of a pigeon, froin the middle Cretaceous of Western Kansas ; related 
to Ichthyornis. The two known specimens are preserved in the Yale ]\Iuseum. 
27. BAPTORNIS ADVENUS. 
Bapiornis advenus, Marsh, Am. Journ. Sci., xiv, July, 1877, p. 86. — Id., Journ. de 
Zool., vi, 1877, p. 387. — Id., Odout., 1880, p. 192, figg. 37-39. 
Based upon a nearly perfect tarso-metatarsal, closely resembling the same part of Hesper- 
ornis, and indicating an aquatic bird about as large as a loon. From Western Kansas, in the 
same Cretaceous beds with Odontornithes and Pteranodontia. The type, and a second speci- 
men referred to the same species, are preserved in the Museum at Yale College. 
28. GRACULAVUS VELOX. 
GracuJavus velox, Marsh, Am. Journ. Sci., iii, May, 1872, p. 363. — Id., ibid., v. Mar., 
1873, p. 229. — Id., Odont., 1880, p. 194. — Coues, Key, 1872, p. 349. 
A bird about two-thirds as large as a cormorant. The remains were found in the green- 
sand of the middle marl bed, or upper Cretaceous, near Hornerstown, New Jersey, and are all 
preserved in the ]\Iuseum of Yale CoUege. 
29. GRACULAVUS PU3IILUS. 
Graculavus pumilus. Marsh, Am. Journ. Sci., iii, May, 1872, p. 364. — Id., ibid., v, 
Mar., 1873, p. 229. — Id., Odont., 1880, p. 195. — Coues, Key, 1872, p. 350. 
A smaller species than the foregoing, from the same formation and locality. Remains 
also in the Yale Museum. 
Note. Several western species, provisionally referred to the genus Graculavus, have since 
been identified with Ichthyornis, which see. 
30. HESPERORNIS REGALIS. (See p. 63, fig. 15.) 
Hesperornis regalis, Marsh, Am. Journ. Sci., iii, Jan., 1872, p. 56. — Id., ibid., iii, 
May, 1872, p. 360. — Id., ibid., x, Nov., 1875, p. 403. — Id., ibid., xiv, July, 1877, p. 85, pi. 
V. — Id., Am. Nat., ix, Dec, 1875, p. 625.— Id., Geol. Mag., iii, Feb., 1876, p. 49, pi. ii.— 
Id., Odont., 1880, pp. 1-117, p. 195, pll. i-xx. — Coues, Key, 1872, p. 195. — Woodw., Pop. 
Sci. Rev., Oct., 1875, p. 337. — Seeley, Jonm. Geol. Soc, xxxii, 1876, p. 510. — Huxl., 
Pop. Sci. Monthly, x, 1876, pp. 215-218. — Vogt, Revue Scient., xvii, 1879, p. 247. — Dana, 
Man. Geol., 1880, pi. iv. 
Reference to p. 238, anten, will show the essential characters of the order or subclass 
Odontolece, of which the present species is a type. Hesperornis may be tersely characterized 
as a gigantic diver, some six feet in length from the point of the bill to the end of the toes, 
standing over three feet high in the position represented in the above-cited figure. While the 
general configuration of the skeleton may be likened to that of a loon, the conformation of the 
sternum is ratite, like that of struthious birds, and the wings are rudimentary or abortive, only 
a remnant of a humerus being left ; other struthious characters are noted in various parts of 
the skeleton ; the jaws are long and furnished with sharp recurved teeth implanted in grooves, 
but the vertebrae are heterocoelous, or saddle-shaped, and the coccyx is short, as in ordinary 
birds ; most of these characters separating this odontolcous type of Odontornithes sharply from 
both OdontotormcB and Saururce. Comparison of the three Mesozoic genera, Hesperornis, 
