DESGKIPTIOX OF TllK SPECIES. 321 



its being united witli it. The generic character is the same with that of 

 tlie species. 



ACEEIPIIYLLUM ARALIOIDES, sp nov. 

 Plate CLXIII, Fig. 8. 



Leaves of medinm size, in outline fan-shaped, at base subcordate, h\m- 

 ina of the leaf slightly decurrent, cut deeply into three lobes, the lateral 

 ones slightly overlapping the middle one ; the middle lobe the largest and 

 prolonged considerably beyond the lateral ones, broadly elliptical, much 

 narrowed at the base, flared out in the middle and rounded off to a sub- 

 acute end, separated from the lateral ones by a sinus which is widest at bot- 

 tom and directed outwards ; lateral lobes ovate-subacute, turned upwards 

 and slightly outwards ; the upper margin of the lateral lobes convex and 

 directed outward; the outer margin, in its upper portion, nearly straight 

 and directed towards the summit of the leaf; the primary nerves, three 

 in number, the middle one considerably the largest, radiating from the 

 base of the leaf and going one into each lobe ; the}' send off alternately 

 and obliquely branches which curve upwards ; the lateral primaries send 

 off much stronger branches on the lower than on the upper side, and the 

 basal one on each side, as in Amlkcphyllum, much surpasses the others; 

 ultimate reticulation not seen. 



Locality: 72d mile-post; very rare. 



This elegant leaf is a remarkably comprehensive type, combining 

 features of Acer, Sterciilia, Sassafras, and Aralia. It reminds one strongly 

 of ArnJkcphylJum, but lacks the subordinate lateral lobes. 



MKNISPERMITES Lesq. 



This genus, like most of the angiosperms of modern t}-pe, has but few 

 specimens in the Potomac beds; possibly, as before stated, because the 

 strata that contain them chieHy have yielded very little material. 



Menispermites Virginiensis, sp. nov. 



Plate CLXI, Fig.s. 1,2. 



Leaves large, oi-bicular in shape, with margins undulate or obscurely 

 crenulate; leaf-substance moderately thick; nerves (primary) numerous, 

 MON XV 21 



