PLUMULARIA MEGALOCEPHALA. 31 
flank the hydrotheca on each side; mesial nematophores, one at the distal 
and one at the proximal side of each hydrotheca. 
Gonosome not known. 
Off Boca Grande, from a depth of 105 fathoms. 
The abruptly attenuated distal portion of the internodes of the pinnx 
is sufficient to distinguish this species. The internodes of the stem are 
short, and the pinne are in consequence close set, resembling in this respect 
those of P. jilicula. In the stem each internode carries two nematophores 
which are placed laterally and alternately, and one pair of nematophores 
which is borne by the lateral process. 
Plumularia megalocephala. 
Pl. XIX. Figs. 1, 2. 
Trophosome, — Hydrocaulus irregularly branched, not fascicled; pinnx 
alternate, each borne close to the distal end of an internode of the stem, 
where it is supported on a long stout process of the internode; proximal 
internode of pinna short and destitute of hydrotheca; following inter- 
nodes longer, every alternate one carrying a hydrotheca, and slightly 
longer than the others. Hydrothecx small and shallow, each borne near 
the middle of its internode, and supporting a very large hydranth. Besides 
the supracalycine pair of nematophores, each hydrotheca-bearing internode 
carrying a single mesial nematophore at the proximal side of the hydro- 
theca; intervening internode carrying two mesial nematophores, and short 
basal internode carrying one. 
Gonosome not known. 
Off Alligator Reef, from a depth of 14 fathoms. 
The specimens from which the description has been written were im- 
perfect, and the height to which they had attained could not be determined 
with certainty, but it was probably about two inches. The internode 
intercalated between the hydrotheca-bearing internodes was sometimes 
present, sometimes absent, and was of variable length. The internodes 
of the stem carry two nematophores placed laterally and alternately, and 
one or two pairs on its lateral process. 
Some of the hydranths in the specimens were sufficiently well preserved 
to afford a sketch of their outline. They are of enormous size in com- 
parison with the hydrothece, into which they could never have been 
retracted. The very large pear-shaped body was supported on a slender 
stalk, the only part which lay within shelter of the hydrotheca. 
