S I. GREGARINIDAE.**
CLASS II. RHIZOPODA.
_Order_ 1. _Monera_.**
" 2. _Amoebea_.**
" 3. _Foraminifera_.
" 4. _Radiolaria_ (Polycystines, &c.)
" 5. _Spongida_ (Sponges).
CLASS III. INFUSORIA.**

SUB-KINGDOM II.--COELENTERATA.

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
(_Sertularia_).
_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_).

SUB-KINGDOM III.--ANNULOIDA.

Animals in which the digestive canal is completely shut off from
the cavity of the body; a distinct nervous system; a system of
branched "water-vessels," which usually communicate with the
exterior. Body of the adult often "radiate," and never composed
of a succession of definite rings.

CLASS I. ECHINODERMATA.
_Order_ 1. _Crinoidea_ ("Sea-lilies"). _Ex_.
Feather-star (_Comatula_), Stone-lily (_Encrinus_*).
_Order_ 2. _Blastoidea_* ("Pentremites").
" 3. _Cystoidea_* ("Globe-lilies").
" 4. _Ophiuroidea_ ("Brittle-stars"). _Ex_.
Sand-stars (_Ophiura_), Brittle-stars (_Ophiocoma_).
_Order_ 5. _Asteroidea_ ("Star-fishes"). Ex. Cross-fish
(_Uraster_), Sun-star (_Solaster_).
_Order_ 6. _Echinoidea_ ("Sea-urchins"). Ex. Sea-eggs
(_Echinus_), Heart-urchins (_Spatangus_).
_Order_ 7. _Holothuroidea_ ("Sea-cucumbers"). _Ex_.
Trepangs