PROTOZOA. 7 



Phylum. Branch. Class. Subclass, 



f Insecta. 

 Myriopoda. 



Acerata { Arachnida (Spiders). 



" * ' \ Merostomata ( Eurypterids, etc . ) . 



VII. Arthropoda \ f Malacostraca (Lobsters, Crabs). 



| Cirripedia (Barnacles). 



Crustacea -j Ostracoda. 



I Phyllopoda. 

 L Trilobita. 



VI. Annulosa Annelida. 



Cephalopoda. 



Pteropoda. 



Conularida. 



V. Mollusca \ Gastropoda. 



Amphineura. 



Scaphopoda. 

 I Pelecypoda (Lamelli- 

 [ branchiata). 



IV. Molluscoidea* .. i Brachiopoda. 

 ^ Jaryozoa. 



{Anthozoa (Corals). 

 Hydrozoa (Hydroids and 

 Hydrocorallines). 

 II. Porifera (Sponges. 



t n * tit-- j f Radiolan 



L Protozoa Rhizopoda JForamini 



ifera. 



General reference works: 



Miller, S. A. North American Geology and Palaeontology 

 1889 and appendices (lists all Palaeozoic species with reference to 

 literature). 



Boyle, C. B. Catalogue and bibliography of North American 

 Mesozoic Invertebrates, 1893 (with reference to literature), Bull. 

 U. S. Geol. Surv., 102. 



Weller, Stuart. Bibliographic index of North American Car- 

 boniferous invertebrates, 1898 (with synonymy and reference to 

 literature), Bull. U. S. Geol. Surv., 153. 



Phylum I. PROTOZOA. 



These are the simplest types of animals, with a body consisting 

 of a single cell. Only two subclasses build hard structures which 

 may be preserved as fossils. These are the Foraminifera and the 

 Radiolaria. The first build external shells of lime, chitin or agglu- 

 tinated sand particles ; the second secrete more or less internal 

 skeletal elements of silica and generally of an open lattice- like 

 structure. 



* Placed here for convenience so as to bring the Bryozoa and Corals together, 

 many fossil forms of which are superficially alike. 



