154 THE HISTORY OF CREATION 
CHAPTER XIX. 
PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. 
II. Mottusca, Srar-FISHES, AND ARTICULATED ANIMALS. 
Tribe of Molluscs.—Four Classes of Molluscs: Lamp-shells (Spirobranchia) ; 
Mussels (Lamellibranchia) ; Snails (Cochlides) ; Cuttle-fish (Cepha- 
lopoda).—Tribe of Star-fishes, or Echinoderma.—Their Derivation 
from Ringed Worms (Mailed Worms, or Phracthelminthes).—The 
Alternation of Generation in the Echinoderma.—Four Classes of 
Star-fish : Sea-stars (Asteridea) ; Sea-lilies (Crinoidea) ; Sea-urchins 
(Echinidea) ; Sea-cucumbers (Holothuridea).—Tribe of Articulated 
Animals, or Arthropoda.—Four Classes of Articulated Animals: 
Branchiata, or Crustacea, breathing through gills; Jointed Crabs; 
Mailed Crabs; Articulata Tracheata, breathing through Air Tubes. 
Spiders (Long Spiders, Round Spiders).—Myriopods.—Insects.—Chew- 
ing and Sucking Insects.—Pedigree and History of the Hight Orders of 
Insects. 
THE great natural main groups of the animal king- 
dom, which we have distinguished as TRIBES, or PHYLA 
(“types ” according to Bir and Cuvier), are not all of equal 
systematic importance for our phylogeny or history of the 
pedigree of the living world. They can neither be classed 
in asingle series of stages, one above another, nor be con- 
sidered as entirely independent stems, nor as equal branches 
of asingle family-tree. It seems rather (as we saw in the 
last chapter) that the tribe of Protozoa, the so-called primeval 
animals, is the common radical group of the whole animal 
kingdom. Out of the Gastreeada—which we class among 
