IL] 



INCIPIENT STRUCTURES. 



67 



"•-■V/ 



wliicli it cannot otherwise got rid of. But granting this, 

 ^vh;vt would ])e the utiHty of the first rudi^ 

 tnentarii he(/innings of such structures, and 

 how coukl such incipient buddings have ever 

 preserved the hfe of a single Echinus ? It is 

 true that on Darwinian princijdes the ances- 

 tral form from whi<;h tlie sea-urchin developed 

 was dillerent, and must not be conceived 

 merely as an Echinus devoid of pedicellaria3 ; 

 but this makes the dillicvdty none the less. 

 It is equally hard to imagine that the first 

 rudiments of such structures could have been 

 useful to nnij animal from which the PJchinus [i 

 miirht have been derived. Moreover, not st' , 

 oven the sudden, development of the snaj) 

 ping action could have been beneficial with- 

 out the freely movable* stalk, nor could the 

 latter have been efficient without the snap- 

 ping jaws, yet no minute merely indefinite 

 variations could simultaneously evolve these 

 complex coordinations of structure; to denv 

 this seems to do no less than to afifirm a start- 

 ling paradox. 



Mr. Darwin explains the appearance of 

 some structures, the utilitv of which is not 

 apparent, by the existence of certain " laws 

 of correlation." Wy these he means that certain parts 

 or organs of the body are so related to other organs or 

 parts, that when the first are modified by the action of 

 " Natural Selection," or what not, the second are simul- 

 taneously affected, and increase proportionally or possibly 

 so decrease. Examples of such are the hair and teeth 

 in the naked Turkish dog, the general deafness of while 

 cats with blue eyes, the relation between the presence of 

 more or less down on young birds when first hatched, and 



PEmrEIXARt.R. 



(Iinnjrnsfly 

 enlarged.) 



