Natural History of the United States. 203 



dependence of the animal and the plant ; the relations of parasites 

 to animals. Under all these and other heads, we have the old 

 argument of Paley against the accidental origin of the watch or 

 its production by physical agencies, vastly augmented by the 

 great additional stores of fact since collected by naturalists. 



3. The permanency of species in nature and the changes 

 through which the individuals of the species pass. Here we 

 have immutability of structure associated with continued succes- 

 sion of individuals, and that succession often complicated by a 

 series of changes, as in the egg, the caterpillar, the chrysalis, and the 

 butterfly, and some even more marvellous than this. Further, we 

 have these changes in the individual, presenting a singular 

 parallelism with the gradations of rank which our minds invari- 

 ably recognise in distinct species, and on the other hand with the 

 grand succession of species in geological time ; so that in the 

 great march of creation, in the ephemeral life of the individual 

 animal, and in the ideas of order in nature which arise within our 

 minds, we have a resemblance indicating at once the planning 

 Creator and the fact that our own minds are created in his image 1 



4. The union of the whole animal kingdom in one great system, 

 dividing in a regular manner into subordinate groups, and the 

 persistence of this, whether we regard widely separated geogra- 

 phical areas, or the lapse of geological time, indicate thought ; 

 and, when we consider the vastness and intricacy of the subject, 

 thought which the most gifted naturalists are ready to admit 

 transcends the powers of man. 



"We have preferred thus to group, however imperfectly, some 

 of the leading considerations adduced by our author, to avoid con- 

 fusing the reader with too numerous heads ; but we shall give as 

 a specimen of the treatment of the subject, the details of the 

 argument on one of the points least familiar to the general reader, 

 the doctrine of " prophetic types" 



PROPHETIC TYPES AMONG ANIMALS. 



u We have seen in the preceding paragraph, how the embryonic 

 conditions of higher representatives of certain types, called into 

 existence at a later time, are typified, as it were, in representa- 

 tives of the same types, which have existed at an earlier period. 

 These relations, now they are satisfactorily known, may also be 

 considered as exemplifying, as it were, in the diversity of animals 

 of an earlier period, the pattern upon which the phases of the 



