* * * * *
(B) With regard to the difficult question of the position in the system of the Neornithes Odontolcae, a few introductory words of explanation are necessary. In 1872 Professor Marsh bestowed upon two fossils from the Cretaceous deposits of Kansas the names of Hesperornis and Ichthyornis, which he proposed in the following year[[45]] to comprise in a Sub-class Odontornithes, so called from the presence of teeth in the jaws. Subsequently[[46]] he divided this Sub-class into two Orders, Odontolcae and Odontotormae, the former containing Hesperornis, with the teeth arranged in grooves, and the latter Ichthyornis, where they were placed in distinct sockets. His views have been controverted by many writers, but Mr. Lydekker–an authority of great weight in this connexion–while fully admitting the affinity of the first form to the Divers, and the resemblance of the second to the Gull-tribe, proposed in 1891[[47]] to retain the term Odontornithes for a series of birds ancestral to the modern series of toothless Carinatae, for which he adopted the title Euornithes, used in a narrower sense by Dr. Stejneger. It has, however, been decided to follow Dr. Gadow on this point; while the marks of distinction given below make it seem at least probable that, whereas Ichthyornis may be referred to the Carinate division, Hesperornis should be placed in closer proximity to the Ratite forms. Our Neornithes Odontolcae consequently contain the Hesperornithes, the Enaliornithes, and Baptornis, all of which appear to be nearly related.
Fig. 13.–Restoration of Hesperornis. (From Huxley, after Marsh.) × 1⁄13.
Hesperornis regalis, which stood about three feet high, and H. crassipes, of even larger dimensions, had blunt teeth in the grooves of both maxilla and mandible, the number being thirty or more below, but considerably less above, where they did not reach to the anterior extremity. The bill was long and pointed, the rami of the lower jaw being entirely separate; the head was rather small, the neck was long, and the quadrate bone articulated with the skull by one knob only. The sternum was long, broad, and flat, without keel; the furcula was decidedly reduced, the metatarsus was moderate and laterally compressed; there were four toes, all directed forwards and probably webbed; the wing was rudimentary, being little more than a humerus; the tail was fairly long and broad, but had no pygostyle. Enaliornis barretti and E. sedgwicki of the Cambridge Greensand had leg-bones very similar to the above, but being only known from fragmentary remains, their position is uncertain; while the same may be said of Baptornis of the North American Cretaceous strata, which, like the two last-named, is much smaller than Hesperornis.
CHAPTER III
NEORNITHES CARINATAE
BRIGADE I–LEGION I (COLYMBOMORPHÆ). ORDERS: ICHTHYORNITHES–COLYMBIFORMES–SPHENISCIFORMES–PROCELLARIIFORMES
(C) The Neornithes Carinatae, or birds which, with few exceptions, have a keel to the sternum, include all the remaining members of the Class. It is unnecessary to recapitulate the distinctions between these forms and the Ratitae, to be found on p. [26], but it may be well to reiterate that it is the sum of all the characters that constitutes the difference, and to point out that in one or more of the items several of the Carinatae agree with the members of the aforesaid group, though totally at variance with them in the aggregate. Claws on the manus are found on the pollex and index in certain of the Anseres, Cathartae, and Accipitres, and on the pollex alone in some Anseres, Accipitres, and Galli, with individual instances in other birds.
