NO. V2.55. ^'E W SPECIES OF A L G.E— WHITE. 267 
general character as that of the orig-inal of Plate XVII. In portions 
of the impression it presents a slighth' irregularly woven or cloth -like 
mesh striking!}' suggestive of the spongy composition of the living 
Codium. 
The genus Butliotrephiji was described in 18-1:7 l)y HalP as an alga 
characterized by •' Stems subcvlindrical or compressed, branched; 
branches numerous, divaricating, leaf -like; structure vesicular T' The 
species ButhotrepMs antigua^~' from the Calciferous sandstone at Chazy, 
New York, generally cited as the type of the genus, is a distinctly 
algoid form with a narrow, flattened lamina, irregularly branching at 
a wide angle along the imperfectly defined axis, and dichotomous in 
the upper part, with more or less acute, narrowly lanceolate or sub- 
falcate lobes or ultimate divisions. Buthotrephis grac'tliK^ the form 
described b\' HalP' as t^^pical of the genus, resembles a linear-leaved 
Pofanuxjeton. It presents an axial development, although the divi- 
sions fork and are slightly recurved. 
In form, aspect, and even in their supposed vesicular structure the 
Kokomo types appear undoubtedly to belong to the group of narrow 
forms originalh' included by Hall, on the basis of their superficial 
characters, in Buthotrephh. It is, however, understood by all pale- 
ontologists that the discovery of the reproductive organs in the vari- 
ous species of this artificial genus may necessitate their ultimate 
reference to more than one family as well as to seveilil genera. Of 
Hairs species, that most closely resembling the plants in hand is the 
B. succulens*' from the Trenton at Glens Falls, New York. The latter 
agrees in its dichotomizing fronds, lax habit, nearl}' constant width of 
the lamina in passing upward, and the blunt apices of the lobules, 
though diflering. especially from B. divarlcata, by the more distant 
bifurcations, and the less divaricate position of the branches and lol)es, 
while the latter are terete and less truncate. The enlarged apices of 
B. ntwlinl suggest the B. hupjuUca Hall,' from the Clinton, though 
the same feature is slightly apparent in B. 2)tdmata, whose general 
plan recalls that of B. divaricata. BHthotrc2}hlssuhnodosa Hall,'' from 
the Hudson River group, like the B. graclU^ has a somewhat elon- 
gated or axial form of development.' though the lateral divisions are 
dichotomous. 
Of all the species as yet ascribed to this genus that which seems to 
be most closely related to the fossils in hand is the Buthof7'eph/s les- 
' Palaeontology of New York, I, p. 8. 
^Ideui.,1, p. 8, pi. ii, fig. (i. 
^Idem., I, p. 62, pi. xxi, fig. 1. 
^Idem., I, p. 62, pi. xxii, fig. 2. 
^Idem., II, p. 20, pi. vi, fig. 2. 
®Idem., I, p. 262, pi. Ixviii, fig. 3. 
'Certain of the elongated forms of the genus might with convenience in classifica- 
tion be set apart as a distinct section. 
