NEORNITHES 



25 



in number, with two, three, four, and five phalanges respectively, 

 ending in claws, the hallux being directed backwards. The 

 manus had three free digits, and apparently three free metacarpals ; 

 the poUex consisted of two joints, the index of three and the 

 third finger of foiu-, while each had a strong hooked claw at the 

 tip; The hand was furnished with six or seven well-developed 

 primaries, attached to the third metacarpal and the second and 

 third digits, the number of secondaries being ten. The long Lizard- 

 like tail had no terminal pygostyle, but was composed of about 

 twenty-one free post-sacral vertebrae, of which the first twelve each 

 bore a pair of large feathers, similar to those of the wing, with 

 the inner webs broader than the outer, and with decided shafts.^ 

 The Sub-Class NI]OBNITHES may be arranged, as above stated, 

 in three divisions, (A) Neornithes Ratitae, (B) Neornithes Odon- 

 tolcae, and (C) Neornithes Carinatae. The first of these con- 

 tains the Eatite Birds proper and possibly part of the so-called 

 Stereornithes of Patagonia (p. 43), with several fossil forms of 

 doubtful position from England, France, and New Mexico, as will 

 be seen below; the second the Hesperornithes of the Cretaceous 

 Shales of Kansas, the Enaliornitheh of the Cambridge Upper 

 Greensand, and Baptornis of the American Chalk ; the third the 

 Ichthyornithes of the aforesaid Kansas deposits, and all other 

 existing Birds, with various extinct species closely allied to them. 



Of the points of distinction between the Neornithes and the 

 Archaeornithes the most important are that the metacarpals are 

 fused together, the second digit being the longest, and the third 

 more or less reduced ; and that the number of caudal verte- 

 brae does not, as far as is known, exceed thirteen, of which the 

 last five or six combine together to form a pygostyle, except in 

 the Hesperornithes, Eatitae, and Tinamidae, where such is seldom 

 the case.^ The centra of the vertebrae also are concave on one 

 side only, except in Iclithyomis, and perhaps in Enaliornis. The 

 possession of teeth is, of course, exceptional, as is the remarkable 

 loss of the keel of the sternum in the Eatitae. 



It is now generally, if not universally, agreed that Flightless 

 Birds were developed from those that could fly. It does not, 

 however, necessarily follow that the Neornithes are direct 



' A doubtful genus, Laopterijx, lias been described from the Jurassic by Marsh, 

 Ann. Xat. Hist. (5) vii. 1881, p. 488. 



2 H. Gadow, Bronn's Thier -Reich, Aves, Syst. Theil. 1893, p. 90. 



