or the tubes are almost level with the edge of a wall-like ridge
which terminates the sponge above ; margin of tubes simple.
Surface of sponge between the coarse inequalities smooth, imperforate
to naked eje. Texture iu spirit firm but b rittle ; colour
dull and pale umber-hrown.
Main skeleton—very loose primary lines of spicules, about three
spicules broad, running irregularly towards surface, crosscd^ by
secondary tracts of similar character, 2 or 3 spicules broad, at right
angles to the primaries and about ’4 millim. apart. Dermal
skeleton—extremely loose tracts of irregularly parallel spicules,
3 or 4 spicules broad, surrounding roundish or polygonal areas
from -18 to -28 millim. in diameter. Sarcode dense, granular,
yellowish brown, containing much foreign material. _ Spicules
smooth acerate, slighly curved, tapering to fairly sharp points from
centre, more rapidly towards the ends than near the c e n tre ; size
•4 by 'OlO millim.
Hab. Port Darwin, N. coast of Australia, 7—12 fms. ; bottom
sand and mud.
The vertical and horizontal dimensions of the irregular lobes both
vary from about 12 to 22 millim. The specimens are all broken ;
the* greatest length represented among the pieces is 60 millim.
(2 j inches). By the very slight extent to which the tubes which
chiefly characterize the genus are developed, tho species is distinguished
from S. dura, Schmidt; by the large size of the skeleton-
spicules, from S. auloqwra. I t has somewhat the general habit of the
specimen figured by Schmidt (Atl. Geh. pi. v. fig. 8) for the latter
species, and of Thalysias subtriangularis, Duch. de Ponhressin and
Michelotti; but has a more contort character than the latter, and
the spicules are far larger than those of the former. I t is also quite
distinct in habit and spiculation from the form termed Thalysias
triangularis 5y Carter (Phil. Trans, clxviii. p. 287), from Kerguelen
Island, the spicules in this being (as I have ascertained from the
original specimens, now in the Museum) only ’19 to '2 by ’014 to
•016 millim. in dimensions. In Schmidtia (isodictya, Bowerbank)
mirahilis, Bowerbank, another Indo-Pacific species, the spicules are
only about half tho size of the present species, although the habit is
similar. I t is perhaps nearly allied to S . clavata (Balsamo-Crivelli),
Esper, by its general habit and large strong spicules; hut those of
th a t species, as figured by Balsamo-Crivelli (Atti Soc. Ital. v. pi. iv.
fig. 12), are considerably stouter than those of S . variabilis.
52. Amorphina megalorrhaphis.
Carter, Ann. 8; May. N. H (5) vii. p. 368.
A remarkable small specimen, which at first sight appears to be
pedicillate, with a fusiform head, but is in reality horizontal in
growth. I t is a subfusiform mass, which tapers rapidly to a blunt
point at one end, runs out as a long narrow cylindrical lobe at the
other, and is attached by one side of its thickest part, so th at the two
ends mentioned project horizontally outwards to right and left of the
point of a tta c hm e n tth e length (horizontal) is 39 millim. ( liin c h ) ,
greatest (vertical) thickness 8 millim., average thickness of narrow
lobe 2 millim. Colour (in spirit) white ; texture rather firm, harsh
(Carter says “ tender ”). A small aperture, about -3 millim. in diameter,
a t the end of the shorter lobe is the only perceptible vent.
Surface obscurely wrinkled. Spicules as in A . panicea, measuring
‘8 to 1 millim. by *012 to *018 millim.
This specimen agrees well in size and in its general and spicular
characters with those described by Mr. Carter from Ceylon.
Hah. Prince of Wales Channel, Torres Straits, 5 -7 fms.
Distribution. Basse Rocks, Ceylon, Kerguelen Island (Carter)
(Atlantic ?, Carter, I. c.). ’
53. Tedania digitata, varr.
Reniera digitata, Schmidt, Adr. Meer. p. 75, pi. vii. fig. 11.
Reniera ambigua, id. Adr. Meer. Suppl. p. 39, pi. iv. ffg. 8.
Reniera mnggiana, id. Spong. Alg. p. 28.
Tedania digitata et mnggiana, drag, P. Z. S. 1867, p. 520.
Tedania nigrescens, Schmidt, Adr. Meer. p. 74, is probably not
distinct from the above species ; but, as it was not intelligibly described
until after T. digitata, the latter name in any case takes
precedence.
Erom a comparison of the specimens and slides of these different
species in the Museum inter se and with Schmidt’s descriptions, I
come to very much the same conclusion as Schmidt (Atl. Geb. p. 43),
viz. th at they are all mere varieties. Schmidt’s expression is that
it is merely a matter of taste whether they are called species or
varieties. Tho differences in outward form have caused him his
greatest doubts as to their identity ; and it is true that, while some
specimens bear large lobate elevations, others are massive, and
th a t whereas some have large vents, in others they are all small
and scattered. But I find th at all agree in a more or less massive
habit, cavernous structure, and strongly ridged or papillose surface;
whereas the Atlantic form, T. suctoria, Schmidt, and the Chilian
T. tenuicapitata, mihi, have an almost eveu surface.
The forms of the spicules are practically the same in all cases, and
the micro-spination of the heads of the cylindrical “ tibiella” is
undoubted throughout, whereas in the two specified species the heads
are quite smooth.
The Port-Darwin specimens differ decidedly in the proportions of
the acuate spicule, as will be seen below, from the rest. None of
the varieties pointed out seem to stand out with sufficient distinctness
from the rest to receive distinct varietal names. A specimen lately
received from Kurrachee agrees essentially with all the above specimens,
the spicules being only rather sm a ll; the surface is broken
up into a dense mass of slender, almost filiform processes and
lamellar ridges, from 1 to 5 or 6 millim. high.
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