508 DR. BOWERBANK ON SILICEO-FIBROUS SPONGES. [June 15, 
any remarkable characters. The fibres are usually quite smooth ; 
occasionally, however, there are small and very immature rectangulated 
sexradiate defensive organs; but I did not see a single well-produced 
-one. ‘There were a few small portions of the dermal membrane in a 
good state of preservation, upon which there was a rather thick layer 
of sarcode; but I could not detect in it any thing in the shape of 
spicula. The specimen from which the above description has been 
made was in the possession of my late friend Mr. Henry Deane, who 
kindly obliged me with the use of it for description ; and his son, Mr. 
James Deane, has kindly given me the specimen. 
FarrEA SPINosissiMA, Bowerbank. (Plate LVII. figs. 3 & 4.) 
Sponge cup-shaped? Dermis, oscula, and pores unknown. Skeleton 
rectangulated, composed of three or four layers; fibres of the ex- 
ternal ones of rather greater diameter than those intervening, more 
regularly disposed; areas variable in size and form, abundantly 
armed with very long, slender, defensive prickles, projected in various 
directions, more or less incipiently spiuous, spines acutely conical— 
and also sparingly with rather small rectangulated sexradiate in- 
ternal defensive organs. Skeleton-fibre rather slender, usually 
smooth, occasionally furnished with a few acutely conical spines ; 
central canals variable in size, usually slender, occasionally obsolete. 
Sarcode, in the dried state, dark amber-brown. 
Colour, in the dried state, dark amber-brown. 
Hab. Unknown. 
Examined in the skeleton-state. 
I am indebted to my late friend Mr. Henry Deane for the only 
specimen of this species with which I am acquainted. It is a plate 
of skeleton-tissue 8 lines in diameter. It is curved to such an 
extent as would seem to indicate that it had formed part of a cup- 
shaped sponge two or three inches in diameter. In some parts of the 
structure there are as many as four layers of the skeleton-tissue; but 
the number most frequently seen is three. The prominent and most 
distinctive character is the long slender prickles projecting from the 
skeleton-fibres at right angles to their long axis; sometimes one only 
is thus produced, but more frequently two in opposite directions, or 
three are thus projected at about equal distances from a line encircling 
a fibre. They are always very slender; but they differ in length toa 
considerable extent: in some cases their length is about equal to the 
diameter of the fibre on which they are based; but they are fre- 
quently three or four times that length. I could not detect the 
slightest indication of dermal or interstitial membranes with a power 
of 80 linear; nearly the whole of the skeleton-fibres were more or 
less covered by a thin coat of dark amber-coloured sarcode; and 
the long defensive prickles were much more thickly coated with the 
sarcode than the skeleton-fibres; and this coating of the prickles 
was mostly thin at their proximal ends, and gradually increased in its 
thickness to their distal extremities, frequently becoming slightly 
clavate. 
