226 Mr. Westwood's Observations 



not imperceptibly and gradually filled up, and her groups united by in- 

 tervening objects, partaking in a greater or less degree (according to the 

 nearness or remoteness of such intervening objects) of the characters of 

 the thus connected groups, but with which intervening objects we may^ 

 be, in many cases, unacquainted. Whether, in fine, nature (to adopt and 

 enlarge the simile of Linnseus) may be said to leap from group to group, 

 placed imconnectedly at distances firom each other, or to walk step by 

 step by means of groups placed connectedly, but at short distances from 

 each other, or, lastly, to slide along from form to form by means of the 

 gradual intervention of objects connected with and related to each other. 



The remarks of Mr. Kirby upon this point are worthy of considerable 

 notice. He evidently feels inclined to adopt a middle course, and says, 

 with reference to the latter plan, " Were this really and strictly the case, 

 " it seems to follow, that every group or individual species must on one 

 " side borrow half its characters from the preceding group or species, 

 " and on the other, impart half to the succeeding," adding, neverthe- 

 less, the question, " Whether every real species or group has not some 

 " one or more peculiar characters, which it neither derives from its pre- 

 " decessor, nor imparts to its successor in a series ?"* 



The peculiarity of character alluded to must necessarily be variation in 

 structure, and therefore if it be proved that precisely the same pecuharity 

 of structure obtains in more than an individual species, it follows that 

 neither of the above ideas suggested by Mr. Kirby as indications of an 

 imperceptibly gradual course of nature, are consistent with nature, and 

 therefore that a further proof is here adduced, that " varying, though not 

 " violent intervals," do naturally exist in the plan of the creation, which 

 cannot, consequently, be said to slide along in the manner above alluded 

 to. Without, however, professing to offer any decided opinion upon this 

 abstruse, yet interesting question, 1 cannot help remarking, that the little 

 experience which I have had in natural history, has had the effect of in- 

 ducing me to beheve, that nature does not adopt the last of the above 

 plans ; and nothing has tended to produce this belief in a greater degree 

 in my mind, than the knowledge. First, That numberless groups of 

 greater or less value, do actually exist in nature, possessing a simi- 



* Kirby and Spence, Introd. v. 4, p. 358. 



