CHAP. I1.] THE CRUISE OF THE ‘ LIGHTNING,’ ia 
and particles of nourishment into all its interstices, 
and finally passes out by the large ‘osculum’ at the 
top. Over the upper third of the sponge a multitude 
of radiating rigid silicious spicules form a kind of 
ornamental frill, and from the lower third a perfect 
maze of delicate glassy filaments, like fine white hair, 
spread out in ali directions, penetrating the semi-fluid 
mud, and supporting the sponge in its precarious bed 
by increasing its surface indefinitely while adding 
but little to its weight. 
This is only one of the ways by which sponges 
anchor themselves in the ooze of the deep sea. 
Hyalonema sends right down through the soft 
mud a coiled whisp of strong spicules, each as thick 
as a knitting needle, which open out into a brush 
as the bed gets firmer, and fix the sponge in its place 
somewhat on the principle of a screw pile. <A very 
singular sponge from deep water off the Loffoten 
Islands spreads into a thin circular cake, and adds 
to its surface by sending out a flat border of silky 
spicules, like a fringe of white floss-silk round a 
little yellow mat; and the lovely Luplectella, whose 
beauty is imbedded up to its fretted lid in the grey 
mud of the seas of the Philippines, is supported by 
a frill of spicules standing up round it like Queen 
Elizabeth’s ruff. 
The sponges of the deep-water ooze are by no 
means confined to one group. The Hewxactinellide 
are perhaps the most abundant, but corticate sponges 
even, closely allied to those which look so rigid when 
fixed to stones in shallow water, send out long anchor- 
ing spicules and balance themselves in the soft mud 
(Fig. 7); and off the coast of Portugal Mr. Gwyn 
