404 OLDER MESOZOIC FLORAS OF UNITED STATES. 
fracture and reaches to about the center of the trunk. No. 500.75 
lies by the side of this, carrying the summit some distance past the 
center. The figure lies in the position in which the specimens were 
placed for photographing. There was no other position in which 
they could be made to lie for that purpose. It is therefore necessary 
to remember that the base is on the right and the summit on the left, 
so that in order to see the trunk in the position in which it grew it is 
necessary to turn the plate. ; 
Pl. CXXIV shows the innermost and approximately central longi- 
tudinal fracture of No. 500.42, and Pl. CX XV the outer somewhat tan- 
gential longitudinal fracture of the same specimen. Pl. CX X'VI shows 
the two broken sides of No. 500.46, Fig. 1 being the face that matches 
No. 500.42 and Fig. 2 that which joins No. 500.75. Pl. CX XVII shows 
the two sides of No. 500.75 in the same way, Fig. 1 being the fracture 
joining No. 500.42 and Fig. 2 the outer fracture. Pl. CXXVIII pre: 
sents the two sides of No. 500.71, which very nearly joins No. 500.42 on 
the opposite side from No. 500.46. Fig. 1 is the broader and Fig. 2 
the narrower face. Pl. CX XIX represents the basal specimen, No. 
500.59, which is of the same thickness as No. 500.42, and, with some 
loss, a downward extension of it. Fig. 1 shows the face which con- 
stitutes a continuation of the inner fracture of No. 500.42 represented 
on Pl. CX XIV, and Fig. 2 that of the tangential fracture, which is in 
like manner a continuation of the side represented in Pl. CX XV. 
CYCADELLA EXOGENA Ward. 
Pls. CK XX-CXXXVIL. 
1900. Cycadella exogena Ward: Proc. Wash. Acad. Sci., Vol. I, p. 273. 
Trunks small or of medium size (12 to 20 cm. high, 8 to 20 cm. in 
diameter), ellipsoidal, somewhat compressed latterly or (in one speci- 
men) vertically, unbranched; rock hard and fine-grained, light colored 
on the weathered surfaces, dark within, variegated with brown or 
white stripes or spots, of medium specific gravity; organs of the armor 
horizontal; rows of scars making an angle of 50° with the axis in both 
directions (traceable only in one specimen); leaf scars subrhombic, 12 
to 20 mm. wide, 6 to 9 mm. high; leaf bases hard, fine in structure, 
punctate or porous; walls 1 to 3 mm. thick, soft-sandy, and more or 
less decayed, light colored, sunken between the leaf bases, striate or 
-wrinkled, sometimes with a median line or commissure; reproductive 
organs mostly concealed, well developed, generally projecting, 15 by 
25 mm. in diameter, surrounded by narrow bract scars, the central 
portion solid and showing the scars of floral organs; armor 8 to 5 cm. 
thick, definitely but irregularly joined to the axis, the leaf bases pene- 
trating to different depths; wood 2 to 3 cm. thick, clearly exposed on 
longitudinal and transverse sections; cortical parenchyma 1 em. thick, 
