154 THE HISTORY OF CREATION. 



CHAPTER XIX. 



PEDIGf-REE AND HISTORY OF THE ANIMAL KINGDOIM. 

 II. MoLLUscA, Stae-fishes, and Articulated Ajs^imals. 



Tribe of Molluscs. — Four Classes of Molluscs : Lamp-sliells (Spirobranchia); 

 Mussels (LamelUbranchia) ; Snails (Cochlides) ; Cuttle-fish. (Cepha- 

 lopoda). — Tribe of Star.fishes, or Echinoderma. — Their Derivation 

 from Einged "Worms (Mailed Worms, or Phracthelminthes). — The 

 Alternation of Generation in the Echinoderma. — Four Classes of 

 Star-fish : Sea-stars (Asteridea) ; Sea-lilies (Crinoidea) ; Sea-nrchins 

 (Echinidea) ; Sea-cucumbers (Holothuridea). — Tribe of Articulated 

 Animals, or Arthropoda. — Four Classes of Articulated Animals : 

 Branchiata, or Crustacea, breathing through gUls ; 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 Eight Orders of 

 Insects. 



The great natural main groups of the animal king- 

 dom, which we have distinguished as tribes, or phyla 

 ("types " according to Bar 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 a single series of stages, one above another, nor be con- 

 sidered as entirely independent stems, nor as equal branches 

 of a single family-tree. It seems rather (as we saw in the 

 last chapter) that the tribe of Protozoa, the so-caUed primaeval 

 animals, is the common radical group of the whole animal 

 kingdom. Out of the Gastrasada — which we class among 



