428 THE DEPTHS OF THE SEA. [CHAP. Ix. 
pear-shaped things, a centimetre long, with a single 
osculum at the top, and the whisp like a small 
brush. At this stage the Palythoa is usually absent, 
but when the body of the sponge has attained 15 mm. 
or so in length very generally a little pink tubercle 
may be detected at the point of junction between 
the sponge body and the coil, the germ of the first 
polyp. 
Hyalonema lusitanicum, BARBOZA DU BocaGE, the 
species met with in the British seas and along 
the coast of western Europe, appears to be local, 
but very abundant at the stations where it occurs. 
I am still in doubt whether we are to regard it 
as identical with the Japanese species, H. sieboldi, 
GRAY. 
During Mr. Gwyn Jeffreys’ cruise in 1870, two 
specimens of a wonderful sponge belonging also te the 
Hexactinellidze were dredged in 374 fathoms in rocky 
ground off Cape St. Vincent. The larger of these 
forms a complete base of a very elegant form, nearly 
ninety centimetres in diameter at the top and about 
sixty in height (Fig. 67). The sponge came up folded 
together, and had much the appearance of a piece 
of coarse, greyish-coloured blanket. Its minute - 
structure is, however, very beautiful. It consists, 
like Holtenia, of two netted layers, an outer and 
an inner, formed by the symmetrical interlacing of 
the four cross branches of five-rayed spicules ; and, 
as in Holtenia and Rosselia, the sarcode is full of 
extremely minute five and six-rayed spicules, which, 
however, have a thoroughly distinct character of 
their own, with here and there a very beautiful 
rosette-like spicule, another singular modification of 
