From the North Sea. . 89 
innermost layers, by being bent, show that it existed when 
the needle was smaller. ‘This may also possibly be an 
indication that the specimens of Hyalonema examined are old 
individuals. 
The long needles of Hyalonema present a singularity first 
observed by Dr. Gray, and of which no trace is seen in our 
sponge. Their free ends have hooks placed in rings or spirals 
directed towards the thickest point of the needle. Professor 
Schultze expressly remarks that this cannot depend on the 
exterior layers having been partly broken. It is an uncom- 
mon case. 
Professor Schultze, who described the oscula of the flattened 
surface of the head of his great Hyalonema, found this same 
surface in the smaller younger specimens covered by a net- 
work of spicules similar to that which covers the free end of 
Euplectella cucumer, Owen, and E. aspergillum,Owen*. No- 
thing similar is to be found in our sponge. 
The head of the large specimen of Hyalonema examined 
by Professor Schultze shows a great number of circular holes, 
with a diameter of nearly a line, surrounded by bundles of fine 
siliceous needles, radiating in all directions from their edges. 
They are not at all to be found in our sponge. Professor 
Schultze regards them as “ chimneys”’ (that is, oscula) ; but 
these are situated, as shown above, in Hyalonema as in our 
and many other species, on the free surface of the head. Pores 
for entering currents they cannot be. In their present form 
they are probably foreign to the structure of the sponge, tubes 
formed by the same parasitic zoophyte which Prof. Schultze 
discovered in their yellowish-brown clothing, and the urti- 
cating organs and arms of which he recognized. 
In looking back on what is said above—the differences 
(which may depend partly on distinction of species or different 
ages, partly on incomplete observation), the affinities in the 
most important points (in the form of the head, with its great 
oscula on the free surface, the spicules in its interior radiating 
around the upper end of a stem composed of spindle-shaped 
siliceous needles)—it seems to follow that the little sponge 
which I have described, from the great depth of the North 
Sea, is a Hyalonema in its complete state, with its stem un- 
injured, and with its roots. But with regard to certain dif- 
ferences—the absence of amphidisci (which seem to belong to 
the propagation), the much shorter spindle-shaped needles and 
their little-developed secondary forms—it seems probable that 
the specimens I have described are young individuals of a 
* Loc. cit. p.9; Owen, Trans. Zool. Soc. iii. p. 203, pl. 18; Trans. Linn. 
Soc. xxii. pl. 21, see footnote, p. 118, 
