444 THE AMERICAN NATURALIST [^'oL. XLI 



same. With the possibilities arising from more extended com- 

 parison of material representing a wider range of variations, the 

 conviction l^ecomes stronger that the opinion so stated is a tenable 

 one. 



Acer torontoniensis n. sp. — The Don collection embraces a 

 number of specimens, some of them fairly perfect, representing 

 a species of maple altogether unknown, either in the fossil or the 

 living state. This leaf appears to present two principal variations 

 which depend in part upon the relative depths of the principal 

 sinuses and the character of the minor lobes or teeth, but chiefly 

 upon the fact that in one form the base of the leaf is only slightly 

 if at all lobed, while in the other case two large lobes extend down- 

 ward from the insertion of the blade on the petiole and enclose 

 the latter. Two principal veins extend from the base of the mid- 

 rib to the corresponding principal lobes, and two subordinate veins 

 of varying prominence extend diagonally downward from near 

 the same point, into the two minor and variable lobes which form 

 the base of the leaf blade. From this description, as also from 

 the two specimens shown in Fig. 2 it will be seen that this leaf 

 belongs to the same group with our common hard maples. Com- 

 parison with these latter also shows that its nearest representative 

 among existing species is the common rock or sugar maple, Acer 

 saccharinum Wang. Comparing the upper fossil of Fig. 2 with 

 one of the more ordinary types of leaf of the sugar maple, it appears 

 that the chief points of difference are to be found in the form of 

 the sinuses and in the character of the large teeth or smaller lobes. 

 If again we compare the lower fossil leaf in Fig. 2 with the cor- 

 responding type of leaf of the sugar maple, the resemblance be- 

 comes much stronger by reason of the similar basal lobes, which 

 have unfortunately been much broken away in the fossil. The 

 differences noted are such as might well result from changes inci- 

 dent to natural development, whereby the more simple tends in 

 the direction of the more compound, and when to this there are 

 joined the actual resemblances, they suggest a very intimate rela- 

 tion between the existing sugar maple and the fossil, of such a 

 character as to indicate that the latter may be the ancestral form 

 of the former. 



A comparison of leaves of the sugar maple with those of the 



