78 



this species under the name of S. acutilobum, (Figs. 1-2 of the same plate.) 

 In passing from this form to S. cretacewn, Newby., of PI. xii, Fig. 2, no other 

 difference is remarked but that of the sborter medial lobe. There is no differ- 

 ence whatever in the nervation, as seen from the comparison of numerous speci- 

 mens. The two leaves of PI. xi, Figs. 1-2, which I have referred to the same 

 species, S. cretaceum, differ by the denticulation of the outside borders, but 

 by this only, and a number of specimens of intermediate character have this 

 denticulation either obsolete or distinct, or merely on one side of a leaf, while the 

 other border is entire, or, so to say, with intermittent teeth, as marked upon 

 Fig. 3, PL xi, whose upper secondary nerves are either camptodrome curving 

 along undulate or entire borders, or craspedodrome going out to the borders 

 and forming or entering a tooth. Figs. 1-2 of this same plate show the same 

 anomaly. The outside borders of Fig. 1 are positively dentate, while the 

 middle lobe is entire. In Fig. 2 this middle lobe is marked by two teeth. 

 And when we come to the leaves which I have called S. ?nirabile, we have 

 a nervation mostly craspedodrome, and teeth all around the borders except the 

 lower veins, which are still camptodrome. Differences of this kind are 

 remarked in the more or less deep divisions of the leaves; in the basilar 

 borders decurrent more or less along the petiole, which they join, sometimes 

 taa distance, sometimes quite near the point of union of the primary nerves, as 

 seen in PI. xi, Figs. 3-4, and PI. xxvii, Fig. 2. The specimens which repre- 

 sent these vegetable forms are very numerous, and it is only after long com- 

 parison of them and a revision of their characters that I have preserved the 

 name of Sassafras for the description of these leaves, admitting, however, as 

 possible in the future the subdivision of Araliopsis for all the species except 

 that of mudgii. The same observation may be made for these leaves as for 

 other types of the Cretaceous. They may be, and have been considered by 

 authors as complex in their simplicity, as uniting some definite characters 

 with some others still in an embryonic state, already slightly apparent, but 

 not yet distinct enough to allow a clear line of separation between the origi- 

 nal and the derived typical fonns. 



Sassafras mudgei, Lesqx., PI. xiv, Figs. 3-4; PI. xxx, Fig. 7. 



Leaves proportionally long ; lateral primary nerves narrow, at an acute angle of divergence ; medial 

 loue twice as long as the lateral ones ; surface of the leaves polished. 



Sassafras mudgei, Lesqx., American Journal of Science and Arts, he. cit, 

 p. 99. 

 This species is distinct from the others and their numerous varieties by 



