266 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
the frequent and equal dichotomies; the continuit}^ in width of the 
lamina, which is without a central axis or strand; and the very obtuse, 
slightly thickened apices. The greater density or more compact 
organization of the latter is shown by the slight increase of the car- 
bonaceous residue. In many of the lobules the impressions seem to 
indicate groups of compressed, nearl}" contiguous, globular l)odies, the 
largest of which, shown in the upper portion of the hgure, attain a 
diameter of about 2 mm. These globules (?), of varying size, appear 
in some cases to occupy nearly the entire apex of the lo])e. The 
impressions, which are less distinct in passing downward along the 
center of the lobe, are at best a little vague. It is possible that they 
are due only to the mode of cleavage in the denser carbonaceous resi- 
due; but it seems probable that they owe their presence to ditferences 
in the composition of the lamina. They are suggestive of the sporan- 
gia in the lobes of the living F'ucas. 
BUTHOTREPHIS NEWLINI, new species. 
(Plates XVII, XVIII. ) 
Fronds fasciculate from a rather thick, scarcely axial base, the 
divisions forking generally distantly, but equally or nearly so, or 
sometimes subfasciculately, at a moderate or wide angle, the lobes 
often linear, sometimes terminally bifurcated, obtusely rounded and 
denser at the apex; lamina of nearly constant width, though narrow- 
ing slightly for a distance below each bifurcation; texture slightly 
rugose, marked by irregular, very slender, intermingled and tangled tri- 
chomatose or tilamentose elements, those near the center being coarser, 
often threadlike, and more or less longitudinal in their arrangement. 
This species has much in common with Bnthott'ephh lenqnet'euxii 
Grote and Pitt, from which it is distinguished by its narrower and 
much more frequentl}^ forking divisions, the divisions of the latter 
species being much elongated and very distantly forked. 
The trichomanose or rather coarsely tomentose character is distinctly 
visible in the impression of the lower portion of the plant as well 
as at the apices of the lobes. In the lower portion of the frond it 
appears to be produced by a tangle of filaments suggestive of the 
texture of felt cloth, although those nearer the middle of the lamina 
are coarsest. A similar texture is seen in Biithotrephh lesquereuxil 
and, with tiner tilaments (?), in B. divaricata. In the lower part of 
the main division on the right in Plate XVII some of the coarse 
fibroid filaments (?) are by the aid of a weak lens clearh^ seen on the 
surface of the carbonaceous residue. No trace of fructification is 
recognizable. 
The fragment illustrated in Plate XVIII is here regarded as a more 
delicate or perhaps younger example of the B. newlhiL although the 
more slender proportions of the divisions and the more delicate texture 
possibl}^ merit a varietal distinction. The surface is of the same 
