18 CRETACEOUS AND TERTIARY FLORA. 



disagreement in the affinities of its species has been explained in the 

 remarks following the description of the genus. I have now to add still 

 to this division two leaves recently communicated from Kansas, represented 

 in pi, iii, fig. 1, and pi. viii, fig. 4. They fully confirm the former obser- 

 vations. By the outline of the leaves, their craspedodrome nervation, 

 and the presence of two pairs of secondary veins under the primary ones 

 and at a right angle to the midrib, they represent a species of Protophyllum ; 

 but the border base of the leaves is truncate, not subpeltate, and by this 

 difference the leaves are rather referable to Credneria, from which, how- 

 ever, they differ by the veins as well as their divisions, being all craspedo- 

 drome, and by the truncate, not cordate, base of the leaves. I formerly 

 published a short description of them under the name of Credneria'? micro- 

 phylla. It now seems that, by their evident relation to Froto'pliylhim quad- 

 ratum, they have to be admitted in this last generic division, an opinion 

 which may be put at naught by the discovery of specimens pointing to 

 another reference for these leaves. 



We have, also, an addition of three new species to the group of Cre- 

 taceous plants described under the generic name of Menispermiies. In 

 this case, however, there is no difficulty whatever in conformably uniting 

 into a definite group the characters of the leaves which, round, ovate, or 

 oval, with borders entire or undulate, have a common generic affinity, 

 indicated by their nervation. In order more clearly to bring into view the 

 relation of the undulate-lobed forms of leaves described in the "Cret. Fl." 

 (pi. XX, figs. 1-4, and pi. xxv, fig. 1), I have represented (pi. xv, fig. 4) 

 a finely and wholly preserved leaf of Menispermites obtusilobus, which, 

 though small, is easily identified with the large one of "Cret. Fl." (pi. xxv, 

 fig. 1). Now, comparing it to figs. 2 and 3 of the present pi. xv, the 

 identity of nervation is defined by the five basilar veins, with a thin pair 

 of marginal veinlets underneath; and by the upward direction of the 

 internal lateral veins, which in fig. 4 ascend to above the middle, pass 

 still higher in the short oval leaf, fig. 3, and reach nearly to the obtuse 

 point in fig. 2. The subdivision of the tertiary veins is in all the leaves 

 of the same type, and the shape of the leaves or their outlines are mere 

 modifications, depending upon the direction of the veins. The leaf, fig. 3, 

 is peltate from the point of attachment of the petiole near the middle. 



