62 SPONGES 
The water system is rather more difficult to make out in these sponges 
than in the Horny Species. The incurrent openings and cilia cells are much 
smaller, and the connection between these cells and the excurrent system is 
somwhat obscure. 
In one of the southern sponges of this group, whieh I found in Nassau Har- 
bor, Feb. 1897, a singular species, which in mature specimens has no attachment 
for any abject, but rolls about on the bottom, and which I believe to be unde- 
scribed, for I can find nothing answering to it in any of the works on sponges, 
under a common magnifying lens the surface shows numerous granulations, 
among which are depressions, in each of which is an orifice very minute and 
evidently with a closing membrane. (See Fig. 35, A, where I give five of 
these orifices.) Each of these orifices opens into a tube which passes through 
a dense, hard skin which measures about .15 in thickness. Inside this skin, 
which is blaek in colar, we find the tubes opening into a soft, fleshy mass, 
which is grayish orange in color, and filled with numerous needle-like spicules 
which cross one another in all directions without any apparent systematic ar- 
rangement. Among these spicules are many connected tubes, small in size, 
none more than about .05 in diameter, but which are occasionally enlarged 
into cells which must be occupied by cilia. As there are no orifices on the entire 
surface of the sponge, larger than Ihave described above, some of these must 
be excurrent openings and some incurrent, but the whole system is so compli- 
cated, that it is difficult to trace any of the tubes with certainty. (See Fig, 
35, B, where I have givena slightly enlarged view ofa section of the outer 
covering of this sponge, and some of the tubes Within. ) 
