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to a chess-board, beeause of the structure of the radial tubes
which resembles that of Ascanclra Sclmiidtii H. The mouth of
cloaca is furnished with a ciliary fringe of very long acerate
spicules. This peristome extends only one mm outside the
true osculum, but 5 mm into the cloaca of the sponge. On
issuing out of the sponge it is surrounded by a fringe of
tri-radiate spicules.
Skeleton. The skeleton consists of triradiate,
quadri-radiate spicules, of large acerate from dermis and peristome,
and of very minute, straight or slightlv curved acerate spicules.
Triradiate spicules (Piate 22, fig. 7—12). These spicules are
numerous and more variable in this species than in otlier
Oalcispongise which I have seen. The ravs are often nearly
of the same diameter and length, but there are not rarely
triradiate spicules, which have two rays of the same size and the
third shorter, as in fig. 7.
Triradiate spicules of the radial-tubes, figured in Plate
22, fig. 11, are very characteristic for this species; the lateral
radii are not of the same length, the proportion between
the lengths being 2:1. Triradiate spicules, figured in the
same Plate, fig. H, are not numerous and not tvpical for the
species.
Quadriradiate spicules (Plate 22, fig. 13). The spicule of this
kind are exceedingly rare. The proportion between the apical
and the other rays is about 2 : 1.
The length of the rays of the triradiate and
quadriradiate spicules varies very much. The length of the two
short rays of the spicule, figured 12, is about 0,i5 mm, ali the
other triradiate and quadriradiate spicules being figured in
the same proportion.
Tlie large acerate spicides from dermis and peristome (Plate
22, fig. 3—4). These spicules vary much in length: from
one mm to 5 mm. The spicules of the peristome and dermis
are almost of the same diameter, the first a little longer.
Con-sequentlv the peristome is not as usual composed of linear
acerate spicules.
The minute acerate spicides (Plate 22, fig. 5—6). The spic-ules
of this kind are exceedingly minute, being only 0,07 mm in
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