TABULAR VIEW OF THE CHIEF DIVISIONS OF THE ANIMAL KINGDOM.
(Extinct groups are marked with an asterisk. Groups not represented at all as fossils are marked with two asterisks.)
Animal simple or compound; body composed of “sarcode,” not definitely segmented; no nervous system; and no digestive apparatus, beyond occasionally a mouth and gullet.
CLASS I. GREGARINIDAE.**
CLASS II. RHIZOPODA.
Order 1. Monera.**
" 2. Amoebea.**
" 3. Foraminifera.
" 4. Radiolaria (Polycystines, &c.)
" 5. Spongida (Sponges).
CLASS III. INFUSORIA.**
Animal simple or compound; body-wall composed of two principal layers; digestive canal freely communicating with the general cavity of the body; no circulating organs, and no nervous system or a rudimentary one; mouth surrounded by tentacles, arranged, like the internal organs, in a “radiate” or star-like manner.
CLASS I. HYDROZOA.
Sub-class 1. Hydroida ("Hydroid Zoophytes"). Ex.
Fresh-water Polypes,** Pipe-corallines (Tubularia), Sea-Firs
Sub-class 2. Siphonophora** ("Oceanic Hydrozoa").
Ex. Portuguese Man-of-war (Physalia).
Sub-class 3. Discophora ("Jelly-fishes"). Only known as
fossils by impressions of their stranded carcasses.
Sub-class 4. Lucernarida ("Sea-blubbers"). Also only
known as fossils by impressions left in fine-grained strata.
Sub-class 5. Graptolitidoe* ("Graptolites").
CLASS II. ACTINOZOA.
Order 1. Zoantharia. Ex. Sea-anemones**
(Actinidoe), Star-corals (Astroeidoe).
Order 2. Alcyonaria. Ex. Sea-pens
(Pennatula), Organ-pipe Coral (Tubipora),
Red Coral (Corallium).
Order 3. Rugosa ("Rugose Corals").
" 4. Ctenophora.** Ex. Venus’s Girdle (Cestum).