300 Mr. H. J. Carter on new Species of 
by the presence of short spines on the shell itself. At the 
same time, as with the lip so with the branches, the whole 
spine may have been replaced by the polypary of the Hydrac- 
tenia; yet then the shell could not have been either of those 
mentioned, especially as the largest and greater number of 
branches are to be found at the extremities; but I shall 
hereafter show that such branches may arise independently of 
the presence of any spine at all on the shell over which a 
Hydractinia may have grown. The large branches are so 
like in form, structure, and colour, together with their spines, 
to the branches of Dehitella atrorubens that no doubt can be 
entertained of the latter being identical with the former, except 
in specification ; while the grooved, anastomosing venation on 
the surface, which does not exist on D. atrorubens and the 
other bush-like forms that I have examined, is equally iden- 
tical with that of the fossil species Hydractinia pliocena 
(‘Annals,’ 1877, vol. xix. pl. viil. fig. 8), which is also pre- 
sent, but less markedly seen, in H. echinata. 
This grooved venation (fig. 4), which is the bed of the 
coenosarcal tubulation in which the whole organism originates 
from the commencement, and is the same in structure and 
function where it forms the first sarcodic lamina on the shell 
(‘ Annals,’ 1877, 2. c. p. 46) as on the surface of the full- 
grown polypary, is more or less repeated as a proliferous 
membrane on the surface of every layer, although it may not 
be so marked in some as in other species ; yet, in the present 
instance, it is as striking in the chitinous polypary of the 
recent H. arborescens as it is in the assumed calcareous one of 
the fossil species Hydractinia pliocena, and will be found 
even more developed in the new fossil species I am about to 
describe. 
Previously, however, it is desirable that I should add a few 
words on the recent species. 
Hydractinia calcarea, Cart. 
Since the description of this was published (‘ Annals,’ 1877, 
vol. xix. p. 50), Mr. Thomas Higgin, of Liverpool, has kindly 
sent me some more specimens on equally small shells of 
Fusus and Nerita respectively, from the same locality, many 
of which possess short branches which, in two instances, 
growing from a specimen on the smooth surface of a Nerita, 
at once point out that they, at all events, do not originate in 
the presence of a spine on the shell which may have become 
covered or entirely replaced by the polypary of the Hydrac- 
tinta, as at first supposed (‘ Annals,’ 1877, /. c. p. 51), but 
are distinct branches or processes similar to those of the 
