1911.] 



NATURAL SCIENCES OF PHILADELPHIA. 



155 



the inner tooth is somewhat smaller than the outer. The remaining 

 19 per cent, had only one tooth. Average dimensions are: height 

 22.4 mm.; width 38.2 mm.; index .585; mean divergence 98° to 102°. 

 This colony, the King Edward woods, is near the Benmore woods and 

 the Cedar Hill woods, but is at present completely isolated from either 

 as well as from other patches of woodland. * From the proprietor of 

 the King Edward Hotel I learn that it has been in its present condition 

 for a generation, and is nearly untouched virgin woods. The constant 

 character of a higher spire seems to have been fixed since the isolation 

 of the colony, as the forms must have migrated in from the direction 

 of Benmore woods or of Cedar Hill, judging from the topography. 



Fig. 14. — King Edward 



Fig. 14 gives the individual dimensions of the shells of this colony 

 and shows distinctly, in the regularity of the frequency curves of the 

 two different dimensions, the unity of the colony and its undisturbed 

 character. The curves here are progressive to the maxima and sym- 

 metrical, they do not indicate any admixture of foreign individual to 

 disturb the integrity of the race, but they do appear to indicate an 

 equilibration of the forms to the environment. The maximum of 

 width is rather sharp, that of height is more gradually attained. As 

 there seems to be in all of this stock a high and a low form intermin- 

 gling, this isolated colony would seem to have nearby attained an equi- 

 librium and fixed the characters of the new high-spired race. Topo- 

 graphically, this woods is lower in altitude than the Benmore or Bloom- 



