140 THE ATLANTIC. (CHAP. II. 
eylinder about 25 centimetres in length by 5 centimetres in di- 
ameter. The walls are composed, as in /. aspergillum, of a 
fundamental square-meshed siliceous net- work, bands of spic- 
ules running longitudinally from end to end of the sponge, and 
transverse bands intersecting these at right angles. The spic- 
ules are in some cases straight and smooth: frequently four 
projecting knobs ranged round the centre of the shaft of the 
spicule show that in essential form the spicule is six-rayed; and 
often one of the side rays is strongly developed, and projects 
to a distance of half an inch or more from the surface of the 
sponge. ‘The spicules are all free from one another, and those 
composing the bands can easily be teased asunder with a pair 
of needles. In this species, as in £. aspergillum, the corners of 
the square meshes are filled up—a pale-brown, corky-looking 
substance reducing them to round tube-like holes, and rising 
into spirally arranged ridges between them; but the ridges, in- 
stead of having a continuous glassy skeleton, have their soft 
substance supported by a multitude of delicate six-rayed sep- 
arate spicules interspersed with the usual minute siliceous stars 
and rosettes. The sponge is hirsute with sheaves of feathered 
spicules, which project from the crests of the spiral ridges, and 
a series of like sheaves of great length replace round the mouth 
the fretted frill of the Philippine Islands form. The mouth is 
closed by a very delicate net-work of a gelatinous substance 
supported by sheaves of fine needles. The correspondence in 
form between its ultimate spicules and those of /. aspergillum 
appeared to be so close, that when I first saw this sponge I sus- 
pected that it might turn out to be the same thing under dif- 
ferent conditions. JI am now, however, convinced that the two 
species are entirely distinct. Huplectella suberea is not the 
only species of the genus living in the Atlantic. Fragments of 
at least two others have occurred to us, but they are too imper- 
fect for description. 
The tube of the Philippine examples of Hup/ectella aspergil- 
