185 



have been usually considered to be " representative " 

 ones, were members, in the first instance, of the self- 

 same assemblages, which had wandered to a distance 

 from their primteval haunts, and were afterwards, 

 through the submergence of the intervening land, cut 

 off from their allies. I have adduced, in a preceding 

 chapter, some remarkable examples in illustration of 

 this hypothesis, an hypothesis which I believe to be 

 the true clue to a very large item of the " specific 

 representation " theory. A considerable number of the 

 Madeiran Helices may be cited (which I have already 

 done 1 *) as, in the strictest sense, representative of each 

 other, and as therefore specifically distinct : and I 

 may add, that it is to island groups that we must 

 mainly look for this system in its full development. 



But, apart from the fact that I would not wish to 

 resign in toto the doctrine of (( specific representation," 

 even as frequently understood (that is to say, as recog- 

 nizable in countries which have been altogether dis- 

 connected since the last creative epoch), and therefore, 

 a fortiori j in what I conceive to be its truer meaning ; 

 there is yet another point on which I would desire to be 

 interpreted aright, whilst endeavouring to substantiate 

 the action of local influences on the members of the 

 insect world. It has been my aim, in the preceding 

 pages, to call attention to the importance of external 

 circumstances and conditions in regulating, within defi- 

 nite limits, the outward aspect of the Articulate tribes. 

 * Vide supra, p. 128. 



