1875.] SILICEO-FIBROUS SPONGES. 2738 
are three or more layers of the skeleton-structure. The fibres of the 
interior of the cup have the greatest number of spines upor them; 
those of the outer surface appear to be nearly spineless. The spines 
are acutely conical; their greatest height rarely exceeds their basal 
diameters. The fibres and the central canals within them both vary 
to a considerable extent in their diameter. One of the largest 
fibres measured ;1,; inch and one of the smallest =4, inch in 
diameter. The average of three that were measured was 54, inch. 
One of the largest canals measured 5;1,; inch in diameter; and a very 
small onein connexion with the large one was >; inch, and the 
average ;,),; inch in diameter. There does not appear to exist any 
definite proportion between the fibre and its central canal, a large 
canal frequently occurring ina small fibre, and a very slender one in 
a stout fibre. In their course threugh the skeleton they usually 
coalesce at each angle of the rete; but it not unfrequently occurs 
that large fibres have two canals running parallel to each other, as if 
each had originated at opposite angles of the rete ; and occasionally 
one or both terminate ina spherical dilatation. A few of the inter- 
stitial spicula fortunately remain entangled in the skeleton-rete. 
They are small, rectangulated, sexradiate forms, with smooth cylin- 
drical radii, and are all of about the same size. Some portions of 
the skeleton-fibres were covered by a very thin layer of sarcode of a 
bark-brown amber-colour. 
The sponge was apparently a skeleton when brought up from the 
bottom of the sea; but although so many important characters are 
absent, those available are sufficiently striking to render its discrimi- 
nation from other nearly allied species satisfactory. 
I have named the species after Dr. Gassiot, through whose 
kindness I have had the opportunity of examining and describing 
it. The specimens were dredged on the 22nd July, 1872, lat. 
14° 8" N., long. 77° 38" W., 800 to 1000 fathoms; and Dr. Gassiot 
in his letter to me states, “ Reliance can be placed on statement of 
locality, depth &c., as the specimens were put into bottles and 
marked by Capt. Hunter, who is a most energetic officer and careful 
observer. 
FarREA POCILLUM, Bowerbank. 
Sponge cup-shaped, contracted ; pedicel short; parietes thin. 
Oscula, pores, and dermal membrane unknown. Skeleton siliceo- 
fibrous ; fibres cylindrical, furnished more or less with short acutely 
conical spines ; rete’ more or less rectangulated, rather irregular ; 
central canal very slender, often terminating abruptly in a cecoid 
manner. Internal defensive organs rectangulated sexradiate, rather 
large, based on the sides of the fibres; radii attenuated, abundantly 
spinous, and also furnished rather abundantly with rectangulated 
sexradiate spicula, small and slender; radii attenuating, incipiently 
spinous. Sarcode dark and opaque. 
Colour, in the dried state, very faint rose-pink. 
Hab. West-Indian seas (Capt. Hunter, R.N.). 
Examined in the dried state. 
Proc. Zoou. Soc.—1875, No. XVIII. 18 
