462 
Transactions of the Society. 
crossing one another at all angles. In specimens mounted in balsam 
may be seen the dark sinuous bands of similar spicules arranged in 
bundles, but not forming a network. The tops of the tubes are 
covered over with a sieve-like reticulation formed of spicules in 
bundles. The spicules are short, cylindrical, acerate, slender, slightly 
curved. Colour of the sponge when dry, pale brown. 
2. Acca r odens sp. n., plate YI. tigs. 2 and 2a. 
Found in a cavity in the stem of a coral (Dendrophy Ilia ramea). 
It is closely allied to the preceding species, but is apparently distinct. 
The entrance to the cavity is a round hole about 1 mm. in diameter, 
and from it projects a ring wall of sponge. The spicules are short, 
slender, acerate, curved, are more slender than those of the last species, 
and the bend at the middle is angular. They are densely matted 
together at all angles. 
From the same cavity was extracted a quantity of minute particles, 
both rounded and angular, like fine sand, apparently produced by the 
gnawing action of the sponge on the coral. Some of these particles are 
represented on pi. YI. fig. 3. 
3. Acca infesta sp. n., plate YI. figs. 4 and 4 a. 
Found upon shells attached to a sponge. It forms a cylindrical 
but somewhat contorted tube, about 1 mm. in diameter and from 2 to 
6 mm. long, issuing from round cavities in the shell. The sides 
of the tube are composed of short curved acerate spicules in two layers, 
in one of which the spicules are placed close together side by side, and 
in the other they are laid transversely to those of the first layer, but 
in an irregular manner, and not close together, uor in bundles. The 
upper end of the tube is covered over by a reticulation of spicules 
arranged in bundles. The spicules are shorter and stouter than those 
of the two preceding species. 
When fresh from the sea this sponge has a pale yellow colour. 
Placed in fresh water it threw off much clear slimy matter. 
Scantilla g. n. 
Spicules of two forms, viz. acerate, and undulating cylindrical 
rods. 
Scantilla spiralis sp. n., plate YI. figs. 5 and oa. 
Pale brown, found in cavities about 1 * 5 mm. in diameter in shell 
of Ostrea cochlear from the coral zone. The spicules are of two 
forms : — (1) acerate, slender, slightly curved, the shorter ones lying in 
all directions irregularly ; the longer ones are laid in bundles, which 
are sinuously consecutive, but do not form a network ; (2) slender, 
