At the bottom of the table I have placed together, under the name "Compound _Protozoa_," those kinds of aggregated _Protozoa_ which show no differentiations among the members of groups, and are thus distinguished from _Metazoa_; and I have further marked the distinction by their position, which implies that from them no evolution of higher types has taken place. Respecting the naming of the sub-kingdoms, phyla, classes, orders, &c., I have not maintained entire consistency. The relative values of groups cannot be typographically expressed in a small space with a limited variety of letters. The sizes of the letters mark the classificatory ranks, and by the thickness I have rudely indicated their zoological importance. In fixing the order of subordination of groups I have been aided by the table of contents prefixed to Mr. Adam Sedgwick's _Student's Text Book of Zoology_ and have also made use of Prof. Ray Lankester's classifications of several sub-kingdoms. _Placental_-----+ | _Aves_ _Mammalia_----+ | _Arachnida_ | | | _Implacental_---+ | _Insecta_ | _Crustacea_ | | | | | VERTEBRATA | | | | | | | | | | _Reptilia_ _Chilopoda_ | | _Amphibia_ ARTHROPODA | | | | _Diplopoda_ _Pisces_ | | _Chætopoda_ _Cephalochorda_ | | CHORDATA ANNELIDA _Urochorda_ | | _Echiuroidea_ _(Tunicata)_ | | _Hirudinea_ +---------+ _Archiannelida_ | | BRACHIOPODA | | ROTIFERA _Dibranchiata_ | | | | _Cephalopoda_ | | +----+ _Tetrabranchiata_ | | | _Crinoidea_ MOLLUSCA ---------------+ | | | +------ ECHINODERMATA _Scaphopoda_ | | | | | _Asteroidea_ _Solenogastres_ | | | | | _Echinoidea_ _Gasteropoda_ | | | | | _Holothuroidea_ _Lammellibranchiata_----+ | | | | _Enteropneusta_ | | | | | | | | | | _Acanthocephala_ POLYZOA --------------------+ | | | | | +--- NEMATHELMINTHES