New Species of Sponges. 53 
other and unite, forming a loop. General diameter, about 
3 to 5 centimetres. Length of root-spicules, 6 to 7 centi- 
metres, Wall of body apparently thin, composed of large 
cruciform spicules, stout at centre and tapering to sharp 
points, and arranged in square meshes, with smaller spic- 
ules of the same forms in the meshes. Length of largest 
spicules and size of meshes, 1 centimetre or less. 
The structure of this sponge places it in Protospongia of 
Salter. It is true that the species of Protospongia are not 
known to have root spicules, but these must have been pre- 
sent in some form, and perhaps the bundle of spicules from 
the Menevian, described by Hicks as P. flabella,' may have 
been of this nature. 
The root of this species is very peculiar in its arrange 
ment. It seems to have been a cruciform spicule, of 
which the rays were bent upward and lengthened, form- 
ing a stalk for the sponge. This would give a firm attach- 
ment, and adapt itself to the gradual rise of the bottom to 
which the sponge was attached. The mechanical proper- - 
ties of such an arrangement of spicula are obviously well 
suited to effect their purpose. 
Salter, in his original description of Protospongia from 
the Cambrian of Wales, compares it with Acanthospongia of 
Griffiths from the Silurian of Ireland, the original specimen 
of which he had seen; but says it has six-radiate spicules. 
He also remarks that the spicules of Protospongia seem to 
be all on one plane.” P. Major of Hicks is a still older spe- 
cies from the Lower Cambrian or Longmynd Series, and 
seemingly of different structure and of much more open tex 
ture than that above described. Matthew has also noticed 
and figured fragments of Protospongia from the Lower 
Camlrian of St. John, New Brunswick. The present spe- 
cies, though somewhat later in age than the foregoing, 
has the merit of presenting a better state of preservation 
and better illustrating the general form, and more espe- 
cially the root-spicules. 
' Hicks’ Jour. Geol. Soc., Vol. xxvii. 
* Journal Geol. Soc., Vol. xx. 
