ITS STRUCTURE, BULK, AND ASPECT. 79 



life-points, as any portion of the dermal bone on whicli they 

 rest. 



It seems truly wonderful, when one considers it, to what 

 minute and obscure ramifications that variety of pattern which 

 nature so loves to maintain is found to descend. It descends 

 in the fishes, both recent and extinct, to even the microscopic 

 structure of their teeth ; and we find, in consequence not 

 less variety of figure in the sliced fragments of the teeth of 

 the ichthyolites of a single formation, than in the carved 

 blocks of an extensive calico print-yard. Each species has 

 its own distinct pattern, as if, in all the individuals of which 

 it consisted, the same block had been employed to stamp it ; 

 and each genus its own general type of pattern, as if the 

 same radical idea, variously altered and modified, had been 

 wrought upon in all. In the Dendrodic (Celacanth f) family, 

 for instance, it is the radical type, that from a central nave 

 there should radiate, spoke-like, a number of arborescent 

 branches; but in the several genera and species of the fa* 

 mily, the branches belong, if I may so express myself, to 

 different shrubs, and present dissimilar outlines. It has 

 appeared to me that at least a presumption against the 

 transmutation of species might be based on those inherent 

 peculiarities of structure which are thus found to pervade 

 the entire texture of the framework of animals. If we find 

 erections differing from one another merely in external form, 

 we have no difficulty in conceiving how, by additions and 

 alterations, they might be brought to exhibit a perfect uni- 

 formity of plan and aspect : transmutation, — development, — 

 progression — (if one may use such terms), — seem possible in 

 such circumstances. But if the buildings differ from each 

 other, not only in external form, but also in eveiy brick and 

 beam, bolt and nail, no mere scheme of external alteration 

 could ever induce a real resemblance. Every brick would 

 have to be taken dow« and every beam and bolt removed. 



