294 Transactions of the eT ee 
of the sarcode most likely represents the porous system of the sponge, 
or in all probability constitutes the more important portion of it. 
In the firmer bands of sarcode intersecting the reticulation, as 
represented at Fig. 3, may also be found larger triradiate and quadri- 
radiate spicula. The minute irregular stellate spicula are abundant 
in the sarcode throughout the sponge, in which also occur the small 
hexradiate and delicately echinate forms depicted at Fig. 10. 
The rootlike bundles dependent from the base are found to 
consist for the most part of attenuate anchorate and attenuate linear 
spicula, having the minute hexradiate and irregularly stellate types 
interspersed among them. 
The oscular system is very distinctly marked on the upper 
surface of the sponge, and, as may be observed in Figs, 1 and 2, 
consists of several large and unevenly distributed oval orifices, which 
give off branches and ramify internally throughout its substance. 
In the specimen figured, the largest osculum occupies the centre, 
having the smaller ones distributed round it; in another example 
which accompanied it, however, there are four or five large oscula of 
equal size, and numerous smaller ones all irregularly disposed. 
The possession of hexradiate spicula makes it necessary to refer 
this form to the group of the Heaactinellidz, treated of at length 
in the November number of the Journal ; but the oscular system and 
other structural characters are so entirely different from what obtains 
in all the species referable to that group which have hitherto been 
recorded, that it will be necessary to create a new division or family 
for its reception. This, however, with fuller particulars of its entire 
structure, I reserve for a future communication. 
The sarcode throughout this sponge is remarkably firm in con- 
sistence, and quite distinct from that which characterizes those species 
of the Hewactinellidz with which we are at present familiar. The 
diverse forms of spicula seem to indicate that this species constitutes 
a connecting link between the Heaactinellide and Tethyide ; further 
study of it is necessary, however, before pronouncing a decisive 
opinion on this point. 
I propose to distinguish this sponge by the name of Dorvillia 
agariciformis : the generic title, at the suggestion of Dr. Gray, in 
honour of Mrs. Dorvill, of Kingsbridge, Devonshire, a lady well 
known for her contributions to natural science, and more particularly 
for the beautiful figures she drew and etched to illustrate the 
‘Testacea Britannica,’ and for the assistance with her pencil she 
rendered Col. Montague in his descriptions of sponges and other 
marine animals communicated to the Linnean and Wernerian 
Societies. The specific one is given in consideration of its agaric- 
like form. 
The specimens from which this description is derived have just 
been purchased by Dr. Gray, for the British Museum, with many 
