46 



are mainly confined to the higher groups. Among the fossil 

 Plants, no new orders have yet been found. There are none 

 known among the Protozoa, or the Mollusea. The Radiates 

 have been enriched by the extinct orders of Blastoidea, Cystidea, 

 and Edrioasterida ; and the Crustaceans by the Eurypterida and 

 Trilobita. Among the Vertebrates, no extinct order of fossil 

 Fishes has yet been found ; but the Amphibians have been 

 enlarged by the important order Labyrinthodonta. The great- 

 est additions have been among the Reptiles, where the majority 

 of the orders are extinct. Here we have at the present date 

 the Ichthyosauria, Sauranodontia, Plesiosauria and Mosasauria, 

 among the marine forms ; the Pterosaiiria, including the 

 Pteranodontia, containing the flying forms ; and the Dinosauria, 

 including the Sauropoda — the giants among reptiles ; likewise 

 the Dicynodontia and probably the Theriodontia, among the 

 terrestrial forms. Although but few fossil Birds have been 

 found below the Tertiary, we have already among the Mesozoic 

 forms three new orders : the Saururas, represented by Archce- 

 opteryx; the Odontotormag, with Ichthyomis as the type ; and 

 the Odontolcag, based upon Hesperornis • all of these orders 

 being included in the sub-class Odontornithes, or toothed birds. 

 Among Mammals, the new groups regarded as orders are the 

 Toxodontia, and the Dinocerata, among the Ungulates; and 

 the Tillodontia, including strange Eocene Mammals whose 

 exact affinities are yet to be determined. 



Among the important results in vertebrate palaeontology, are 

 the genealogies, made out with considerable probability, for 

 various existing animals. Many of the larger mammals have 

 been traced back through allied forms in a closely connected 

 series to early Tertiary times. In several cases the series are 

 so complete that there can be little doubt that the line of 

 descent has been established. The Evolution of the horse, for 

 example, is to-day demonstrated by the specimens now known. 

 The demonstration in one case stands for all. The evidence in 

 favor of the genealogy of the horse, now rests on the same 



