1875.] SILICEO-FIBROUS SPONGES. 275 
skeleton-fibre, but it differs essentially from it in the form of its 
reticular arrangement. 
I have named the genus after my late friend Mr. Henry Deane, 
to whom I am indebted for my knowledge of the sponge. 
DEANEA VIRGULTOSA, Bowerbank. 
Sponge sessile (?), virgultose, solid, irregularly cylindrical. Surface 
even. Oscula, pores, and dermis unknown. Skeleton symmetrical ; 
fibre cylindrical ; central canals large and very distinct. 
Colour, in the dried state, amber-brown. 
Hab. West-Indian seas ? 
Examined in the skeleton condition. 
All that remains of this interesting sponge is unfortunately its 
well-washed skeleton, so that little more can be said of it than what 
apertains to its generic characters; but these are fortunately very 
distinctive. The specimen is 17 inch long, and of an average 
diameter of about 2 lines. Which has been its basal end cannot be 
determined, as both are broken terminations. The substance of the 
Sponge is very compact, there being no central cavity. There are 
no indications on its surface of oscules, and not the slightest remains 
of either dermal membrane or sarcode. 
When a section of the sponge is made at right angles to its long 
axis, mounted in Canada balsam and viewed with a power of 100 
linear, its structure is beautifully displayed. Its singular confluent 
rotulate rete is as regular as that of Iphiteon, described and figured 
in the ‘ Proceedings’ of this Society for May 1869, p. 323, pl. xxi. 
figs. 1 & 2. No other form of structure occurs in the skeleton; 
and whether we view a transverse section, a longitudinal one, or 
the surface of the sponge, the same rotulate structure is presented 
to the eye. 
The canaliculated structure is very strongly produced. The canals 
radiate from the axis of each rotulum, and usually appear to be con- 
tinuous through the whole of the skeleton-structure ; occasionally, 
but not frequently, a single ray will be entirely destitute of the 
central canal ; but this is the exception, not the rule. The skeleton- 
fibres vary in diameter from ;3; inch to z4,; but the general 
average is about =}, inch. The central canals are large in pro- 
portion to the size of the fibres; their range in diameter is from 
To oo ch to 35/55 inch, but their average diameter is about 7-55 
inch. They are not always in proportion to the size of the fibre, the 
largest canals being frequently in the smallest fibres. 
Since the above description was written I have received a small 
fragment of another specimen of the sponge. It is a piece of a 
similar small cylindrical mass, about 3 lines in length and rather less 
inits diameter. In this specimen there are remains of sarcode thinly 
coating some of the skeleton-fibres ; andin many of them the canals 
are lined with a sarcodous membrane of a dark amber-brown colour, 
a strong evidence that the sponge was in a living state when taken. 
No spicula of any description could be detected in any part of the 
18* 
