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shallow depressions, covered by a glabrous semitransparent membrane,
rendered rough by the projection of tho low ends of the
primary fibres, -25 to -5 millim. apart (many smooth patches occur) ;
texture in spirit brittle, compressible (specimen No. 1), rather tough,
elastic (specimen No. 2 ); colour pale greyish (specimen No. 1) or
reddish brown (specimen No. 2). In te rn al structure cavernous,
loose. Vents mimerons, scattered, circular or oval, leading deeply
into sponge ; diameter 1’5 to 3 millim.
Main skeleton regular, rectangular in arrangement; primary
fibres set a t right angles to surface, -18 to -35 millim. apart, -013
to -03 millim. thick ; secondary fibres at right angles to primaries,
•18 to -35 millim. or upwards apart, similar to primaries in proportions
; fibres wholly composed of foreign bodies united by an almost
colourless, not dense, substance. Dermal skeleton formed by small
foreign bodies scattered abundantly over the dermis, tending to
aggregate into slightly denser anastomosing tracts about -14 millim.
broad, enclosing rounded meshes about -18 to -53 millim. in diameter,
and by the cylindrical spicules of tho sponge, which by loose
aggregation form tracts, about 4 to 6 spicules broad, below the
skeleton of foreign bodies, the tracts branching and anastomosing
not unfrequently, and ending freely on the surface in slightly
expanding tu f ts ; sarcode suhtransparent, granular, colour a warm
brown (slightly iu specimen No. 1, strongly in specimen No. 2, in
which it is more dense. Spicules:—(1) Slender acerate, smooth, with
very slightly enlarged subpyriform basal end, the other end rather
bluntly pointed ; size about '16 to -19 by -0021 by -0032 millim.:
forming part of dermal skeletou and scattered over main skeleton-
fibres. (2) Contort bihamate, smooth, curve moderately strong,
points sharp, suddenly and sharply bent inwards ; size -032 by -002
millim.: abundant in subjacent tissues. (3) Tridentate equianchorate,
shaft well curved, about -0016 millim. th ic k ; teeth slender,
sharp, curved inwards, about ‘008 millim. long; spicule-022 millim.
long. Foreign bodies small in specimen No. I ; large, for tho most
part, in specimen No. 2.
Hah. Specimen No. I : Prince of Wales Channel, Torres Straits,
7 -9 fm s.; bottom sand. Specimen No. 2 : Port Jackson, 0 -5 fms.
Two specimens in spirit. No. 1 has apparently been torn from a
larger mass; it is much penetrated by some thin Algas, on which it
seems to have grown much as Amorphina panicea grows over weed;
it measures 60 millim. by 22 millim. in its two chief dimensions.
No. 2 is somewhat compressed on one side, and measures 36 by
19 by 12 millim. The anchorate spicule is scarce in one of the
specimens (th a t from Port Jackson), while it is abundant in the
other.
The variability in colour aud texture, and jierhaps in the secondary
fibres, is considerable, hut not surprising, considering the
distance between the stations at which the specimens were obtained ;
in other points the agreement is close. The species is a very distinct
one, differing from both Marshall’s species in the presence of
a well-defined reticulate skeleton and of an anchorate flesh-spicule,
441
in the slenderness of the bihamate spicules, and the almost absolute
absence of a head to the very slender linear spicule; the resemblance
m spiculation seems conclusive as to the generic identity of the
three forms, in spite of the remarkable differences in the skeleton,
ih e mulberry-like bodies described by Marshall in P. solida I cannot
see in the present species; when treated with hydrochloric acid
the superficial^ layer of the dermis parts with all hard elements
except the^ spicules and some amorphous transparent fragments.
Marshall himself does not mention these bodies in P. reticulum, so
th at they cannot he of more than specific or individual importance.
The spiculation of Phoriospongia is perhaps nearer to th at of
-gnpMectus than of any other genus. Thus, besides Clathria (see
t . tuherosa, p. 444), we have a second genus of Siliceous Sponges
which may normally exhibit the phenomenon of intussusception
ot sand into the fibre. I t seems to me th at intussusception is the
most probable hypothesis on which to account for the presence of
the sand in this genus, although Marshall, whom I understand to
deVs. cAr i/b Z eC AP horiospongia 1 as pen■e trating and spinnin^g uJp- masses of sand (“ durchziehen und umspinnen Sandraassen, sie zu Klumpen
vereinigeud ” ), may be right in this interpretation of the origin of
the sand in the genus Phoriospongia ; however, in P. fibrosa we
find a real system of fibres which does not appear to occur in P. solida
andreticulum ; and although I have not been able to detect a horny
material, like th at of Dysidea, uniting the sand grains, which might
as held by Bowerbank and MarshaU, pick them up, it seems to me
that, remembering the readiness with which Siliceous Sponges
whether possessing a horny fibre or not, take up foreign bodies,
there is no reason why the sand of Phoriospongia should not be
taken up, and not be due to the penetration of masses of sand by
the sponge._ This view is supported by the spiculation, which is
not Suheritid like th at of Vioa, hut, as above remarked, Desmacidine
; thuqpresence of the spinulate spicule is common to it and
many Desmacidines ; while the absence of the remarkable eversible
funnel which distinguishes the termination of the excretory canal-
system in Vioa seems to indicate a different affinity. Reniera fih u lata,
Schmidt, to which Marshall refers in support of his view th at
bihamates occur in sponges other than Desmacidinidæ, has been
placed by Yosmaer in th at group under the genus Desmacodes,
S/hmidt, apparently not without reason ; and Schmidt (Spong. Atl.
Geh. p. 40) himself inclines to the view of its Desmacidine affinities ;
but the presence of bihamates in Suberitidæ is hitherto unknown.
ECTYONIDÆ.
Ectyonida, Carter, Ann. 8; May. N. H 1875, xvi. p. 133.
Schmidt (Spong. Atl. Geb. 1870, p. 133) grouped Chalinopsis
{=Ectyon) and its allies, with Axinella, Phacellia, &c., under the
heading Chalinopsidinae ( = Echinonemata, Carter, I. c.). Mr. Carter
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