30 
CLASSIFICATION. 
ORDER 2. GYMNOPHTHALMATA, including various kinds of naked-eyed 
medusae. 
Class V. POIjYPI: divided into three Orders : 
ORDER 1. HELIANTHOIDA, including the actmise, sea-anemones, sea-carna- 
tions, or sea-flowers ; also madrepores, or tree-corals, cup-corals, 
brain-corals, &c. 
ORDER 2, ASTEROIDA, including various kinds of zoophytes, called asteroid- 
polypes, or corallines ; as the cock's-comb, sea-pen, sea-feather, sea- 
fan, dead-man's-toes, dead-man's-fingers, &c. 
ORDER 3. HYDROIDA, including various kinds of branched and jointed zoo- 
phytes, as the halecium, sertularia, sea-bristles, sea-fir, &c. ; also the 
hydra, &c. 
Division V. PROTOZOA. 
Divided into three Classes and various Orders, as follows : 
Class I, INFUSORIA : divided into two Orders : 
ORDER 1. STOMATODA, including the vorticella, or bell-animalcules. 
ORDER 2. ASTOMATA, including the mouthless infusoria. 
Class II. PORIFERA S including the sponges. 
Class III, RHIZOPODA : divided into two Orders . 
ORDER 1. POLYTHALAMIA, including the associated proteus. 
ORDER 2. MONOSOMATA, including the solitary proteus, as the arcella, 
amoeba, &c.^ 
OF SPECIES BELONGINa TO THE ANIMAL KINGDOM. 
The preceding Classification embraces the entire animal kingdom, exclusive of fossil remains. 
The number of species belonging to this has been estimated as follows : Mammalia, 2,000 ; Birds, 
6,000; Reptiles, 2,000; Fishes, 10,000 ; MoUusca, 15,000 ; Articulata, 200,000; Radiata, 10,000 : 
making 245,000 in all. 
It is supposed the fossil species may be equal in number to these, making nearly half a million. 
It is highly probable the actual number of species in the animal kingdom is even beyond this. 
All these, however, are not yet actually known. About a century ago, the whole number of as- 
certained species did not exceed 8,000 ; but such have been the earnestness and activity of re- 
search, that 60,000 species have now been made out and described. Specimens of about 1,500 
mammalia, 5,000 birds, 1,500 reptiles, 6,000 fishes, 10,000 moUusca, and 50,000 insects and other 
articulata are in the various collections and museums of Europe. 
* It is proper to state that in preparing this Classification, and in various parts of the preceding Introduction, we 
have been largely indebted to the excellent Natural History of W. S. Dallas, London, 1856, 
