Ixv. 



as a fossil in the Eocene beds of the Isle of Mull, but is extinct in 

 Europe. The other, Davilia tenuifolia, a delicate little plant, is a 

 genus, not now represented in America, and having only one 

 species in Asia. Such instances of specific persistence, accom- 

 panied by great changes of habitat, are very instructive as to the 

 permanence of species. These Lamarie beds contain several 

 Conifers Glyptostrobus^ Taxodtum, and Taxus. The Ginko tree 

 Salisburia appeared in the Jurassic age. The Lamarie beds were 

 laid down when the climate was equable and temperate, the land- 

 area extensive, and a uniform flora existed from the Arctic Seas, 

 through the central plateau of America, far to the south, and 

 along the western coast of Europe. 



Persistency of species is not confined to plants, but extends to 

 animals as well. The earliest are the Protozoa, very simple in 

 their organisation, and small in size ; some are destitute of any 

 external covering, others are protected by a shell, or a less solid 

 enduement. Rhizopods and Infusoria are typical Protozoa. 

 There are intermediate and inferior organisms, which, like animals, 

 have freedom of movement, and appear at the same time to have 

 affinities to plants. Haeckel proposed for them a new order, 

 that of ProtistSj which cannot be referred with any certainty either 

 to animals or plants. He placed the Infusoria without any 

 reserve, as well characterised animals. Certain groups of 

 Rhizopods occupied an important place in the Primitive beds, 

 in which their remains are well preserved ; on the contrary 

 Infusoria are very little known in a fossil state, no traces of the 

 past existence of Monera and Amoeba have yet been obtained, and 

 from their soft-bodied nature, they are never likely to be. 

 Foraminifera, however, occur in the earliest Palaeozoic beds. 

 Dentalina and Lagena have passed through all the geological ages 

 from the Silurian to the present time, with an extraordinary per- 

 sistency of form. The claim for Sponges to a place in the Animal 

 Kingdom had been long canvassed, but of this there is now no 

 doubt. The Sea-anemone was once considered a flower, and the 

 Actinizoa found on living Corals were thought to be the blossoms 

 of an Anthozoan Zoophyte. Among the Anthozoa, the Madreporidae 



