Sponge from the Philippine Islands. 379 
head (including the arms) being about as broad as long, viz. 
1-150th of an inch (fig. 9)—that is, about three or four times 
less in diameter than the thickest part of the shaft, which is 
much nearer the free than the fixed end. 
The spicules of the latticework (fig. 2) are of three kinds :— 
1, a strong five-rayed or nail-like form, consisting of a vertical 
shaft pointed at one end, and carrying at the other four rather 
long, robust, horizontal arms at right angles to the shaft and 
to each other; the shafts of these spicules are fixed in the 
general sponge-mass vertically ; and the arms of each extend 
towards, meet, and overlap those of others horizontally, thus 
forming the square-shaped meshes of the larger latticework ; 
2, long, slender, fusiform, acerate spicules, which lie upon the 
arms of the large nail-like forms longitudinally, and help to 
strengthen the lines of the latticework; 3, small crucially 
headed spicules of the nail-like form, the shaft of which is 
much longer than the arms of the head, and furnished all 
round throughout the greater part of its length with long 
spines, which are bent obliquely outwards and extend to the 
pointed end, giving the whole a plumose appearance; the arms, 
which are nearly smooth, are pointed, opposite, and at right 
angles to the shaft and to each other (fig. 8). These spicules 
are generally found in pairs, with the shafts close together and 
the arms obliquely crossing each other as they rest upon those 
of the large nail-like spicules; also throughout the areas of 
the large meshes, where their nail-like heads are fixed in the 
dermal membrane, with the common shaft standing outwards, 
and the points of the arms touching those of their neighbours, 
so as to divide the large meshes of the latticework into a 
number of smaller ones, each of which is converted into a 
round hole or pore by the dermal sarcode. 
But amongst the spicules of the surface must be mentioned 
a very large, stout, acerate spicule, closely resembling that 
found by Mr. H. J. Carter m the stem of Crateromorpha 
Meyer’, measuring in its average largest size about 4-12ths 
of an inch in length by 1-66th at its broadest part. It is 
occasionally found under the arms of the large nail-like 
spicules, but generally together with long slender acerates 
(both smooth and spined), composing strong fibrous lines, 
which contribute to support the latticework and to connect 
it with the general sponge-mass (Pl. XXII. fig. 1). 
The spicules of the general structure are :—1, large and 
small nail-like forms, with smooth shafts and arms; 2, long, 
slender, smooth, fusiform acerates; 3, the same, with four 
large tubercles on the middle of the spicule, or abortive rays ; 
4, long, thin, fusiform-acerate, thickly spined throughout, the 
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