JURASSIC CYCADS FROM WYOMING. 189 



only a thin piece is missing between Nos. 500.136 and 100.210. If tliis 

 were present, we should have nearly half of a small compressed trunk. 

 No. 500.470 joins No. 100.338, and No. 500.594 joins No. 100.312. These 

 last four, with about a dozen other fragments, undoubtedly represent the 

 type trunk, and the structure indicates that they lay very close to the 

 type No. 500.71 (see PI. cxxviii). Nos. 500.178 and 500.422 constitute 

 another complementary couple of a somewhat different class, but evi- 

 dently belonging to this species. They show the internal structure 

 very clearly and also considerable of the surface, indicating a much 

 compressed trunk probably larger than that to which the type speci- 

 mens belong. Nos. 100.258 and 100.275 also go together and represent 

 still another trunk not otherwise represented. They all have the char- 

 acteristic internal structure and surface markings of the species. No. 

 100.245 is the largest specimen, weighing 0.9 kg. It is a slab from 

 one side of a trunk, showing considerable of the surface and a broad, 

 smooth, tangential fracture. 



PI. LII, Fig. 2, is a side view of the triangular section resulting 

 from joining Nos. 500.178 and 500.422, and PL LII, Fig. 3, the internal 

 structure of the inner fracture of No. 500.422. PL LII, Fig. 4, shows 

 one of the fractures of No. 500.136, and PL LIII the tangential fracture 



of No. 100.245. 



Cycadella exogena Ward. 



PI. LIV. 



1900. Cycadella exogena Ward: Proc. Wash. Acad. Sci., Vol. I, p. 273; Twentieth 

 Ann. Rep. U. S. GeoL Surv., 1898-99, Pt. II, p. 404, pi. cxxx-cxxxvii. 



A limited number of specimens, most of them fragments, are 

 referred to this species. By far the largest and most complete is No. 

 500.514, which weighs 2.04 kg., although the armor has disappeared 

 from more than half of it and a considerable part of the axis is also 

 wanting. This specimen is difhcult to orient, as neither base nor sum- 

 mit is preseiat and the direction of the axis is not clear, while the surface 

 is covered with ramentum, but one of the fractures which passes through 

 the entire woody zone and the armor was found to join one of the planes 

 of fracture of the small specimen No. 100.249, adding considerable to 

 the trunk. This specimen weighs 0.45 kg., making the total weight 



