66 
AUG. F. FOERSTE 
Specimen 10 shows very well the reticulation among the fibers 
forming the body of the frond. The hair-like fibers extending 
beyond the margin of the frond are also well preserved. Speci- 
men 18 B exposes very well some of the hair-like fibers near the 
lateral margin of the frond. The appearance of lobation is due 
to oblique wrinkling. Frond B on specimen 18 is one of the best 
specimens to suggest the presence of reticulations among the 
fibers of the frond. Near the median line of the frond 3 meshes 
occur in a length of 1 mm. ; at a greater distance from the median 
line they are more irregularly arranged. Of the larger black 
dots, 5 occur in a length of 1 mm. Specimen 21 shows along its 
right margin several of the series of black dots regarded as 
locating the direction of some of the hair-like fibers. 
In specimen 23 the right hand frond is seen under the micro- 
scope to be crenulated rather than lobed, the appearance of 
lobation being due in part to a twisting of the frond near the 
inner angles of the points of indentation. The median rachis- 
like film is poorly preserved, but may be traced readily. Retic- 
ulation among the fibers of the frond is evident. The hair-like 
fibers extend more than 1 mm. beyond the margin of the frond, 
and some of them may be traced to points of attachment on its 
flat surface. 
In specimen 22 the rachis-like film of the median part of the 
frond is 0.6 mm. wide, the corresponding parts of the lateral 
lobes being 0.25 mm. wide. The reticulated fibers produce 
meshes from 0.2 mm. to | mm. long. Along some of the hair- 
like fibers there are 6 or 7 dots in a length of 0.5 mm. 
In specimen 24 the main rachis is 0.6 mm. wide, while the 
corresponding parts of the lateral lobes are 0.4 mm. wide. The 
latter are so well preserved that on macroscopical examination 
the frond appears lobed, while microscopically the frond is seen 
to be merely crenulated. 
Specimens with crenulated margins. — Specimens with the 
lateral margins of the frond-like expansions crenulated rather 
than lobed are so common that eventually they may be regarded 
as more normal than the lobed specimens of Leveilleites. Speci- 
mens with crenulated edges are represented by figures 2, 3A, 
