176 THE ANIMAL KINGDOM. 



leaves out one important division of the animal kingdom, viz., 

 the Mollusca. To this it may be replied, that the Mollusca, 

 especially in its lower forms, seem, to he but a higher branch 

 of the Radiata. Some of the lower or univalve shell-fish 

 grow in clusters, or united compartments, almost as one ani- 

 mal, and in this essential characteristic are somewhat allied 

 to the polipiaria, which comprises one class of the Radiata. 

 This quality of growing in clusters, or connected compart- 

 ments, is preserved even by some of the bivalves, such as 

 muscles, oysters, etc. The detached bivalves, having locomo- 

 tive powers, seem to be an ascension from these ; and the still 

 higher orders of mollusca, viz., the gastropoda and cephalo- 

 poda, seem to be but higher representations of the same sys- 

 tem of creative design, which, as its lowest expression, evolved 

 the polipiaria and crinoids. 



I have personally observed that the whilk, which is among 

 the higher orders of shell-fish, propagates through the medium 

 of a zoophitic, or vegetable-like, form, with an attached stem, 

 and containing leaf-like appendages or pods, in which the 

 young are brought to foetal maturity. The Radiata and Mol- 

 lusca, therefore; may be considered as comprehended in one 

 general division of the Animal Kingdom, which division, how- 

 ever, should perhaps be designated by some term of more 

 comprehensive significance. 



It is thus seen, that the Animal Kingdom conforms to the 

 same serial and correspondential law which we have seen run- 

 ning through all systems of creation previously contemplated, 

 and which we will hereafter perceive runs equally through still 

 higher developments. And with this, as the highest system 

 of material creation, our more specific classifications of the 

 grand departments of the universe without us, is completed. 



