852 HISTORICAL GEOLOGY. 



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Greek, signifying tvithout teeth. The skull and sleuder bird-like jaws of 

 Pteranodon longiceps Marsh are shown iu Fig. 1422 h, and an upper view in 

 Fig. 1422 a. The fore limbs (wings) are enormous, the hind limbs very 

 small. These animals, as Marsh observes, have several vertebrae anchylosed 

 to act as a sacrum to the pectoral arch (like the sacrum in the 2i6ivic arch), 

 for the support of the powerful wings. The skull alone of P. ingens of 

 Marsh is about four feet long, and that of P. longiceps over three feet. The 

 abundance of their remains in the Kansas beds appears to show that these 

 great bird-billed Pterosaiirs frequented the borders of the Cretaceous sea as 

 its Kingfishers. 



3. Birds. — The Cretaceous Birds, in part, had teeth (like the Jurassic of 

 Solenhofen), as first reported by Marsh from Kansas specimens. One of the 

 species, the Hesperornis regalis of Marsh, five to six feet in height, is repre- 

 sented in Fig. 1423 (reduced to -!■) from an essentially complete skeleton. 

 The figures also illustrate, besides the skeleton, one of the teeth, the jaw in 

 two positions, a dorsal vertebra, and the pelvis. The teeth are fixed in a 

 groove, as in many Reptiles. This large bird had short wings, ostrich-like, 

 with many of the characteristics of a Loon, one of the Divers. Another 

 Kansas bird of different type is the Ichthyornis victor of Marsh, a small 

 bird, with good wings. The fish-like feature to which the name alludes is 

 the biconcave form of the vertebrae. But, with this low-grade feature, it 

 has the teeth in sockets. In the restored skeleton (half the natural size). 

 Fig. 1430, the bones actually found are those of the shaded part. Apatornis 

 of Marsh is a related bird. Marsh has described, also, species of two other 

 genera related to Hesperornis ; namely, Baptornis and Coniornis, the latter 

 from the Fox Hills group, Montana. All the Cretaceous birds have the fore 

 limb greatly modified for wing purposes, bird-like ; but in the Hesperornis 

 it has passed beyond this and become rudimentary, as in the Ostrich. This 

 is in striking contrast with the earlier Jurassic birds, in which the fore limb 

 is more completely and normally a leg than a wing. The toothless birds 

 (or those not yet proved to be toothed) of the Cretaceous beds of New Jersey 

 were related to the Cormorants and Waders. 



4. Mammals. — The Mammals of the Cretaceous thus far discovered are 

 probably all Marsupial or Monotreme, like those of the Jurassic period. 

 The remains are mainly teeth, with a few broken jaws and limbs. The 

 earliest described is the Meniscoessus conquistus of Cope, discovered by J. L. 

 Wortman in the Laramie of Dakota (1882, 1884). Many kinds have been 

 described by Marsh (1889-1892). The following figures are from his plates 

 of 1892. 



The figures 1432-1438 are supposed by Marsh to represent teeth and por- 

 tions of jaws of Marsupials, and the remainder probably of Monotremes. 

 The teeth of the genus Tripriodon have some resemblance to the tooth of the 

 Meniscoessus figured by Cope, and have been referred by Osborn to that 

 species. 



