184 
PACIFIC SCIENCE, VoL XIX, April 1965 
FIG. 28 b. Spirastrella aurivilli Lindgren. Spirasters. 
mens. The tylostyles constitute almost the en- 
tire skeleton of the papillae and are arranged 
in two distinct layers, an inner vertical layer 
and a central layer. A few tylostyles possibly 
constitute a third, dermal layer at right angles 
to the surface. 
SPICULES: Megascleres. Tylostyles, of two 
size groups: (a) large, stout, straight or slightly 
curved tylostyles in which the head is most 
often subterminaL These spicules make up the 
bulk of the skeleton; 500-680 X 18— 33 a*. (b) 
Smaller tylostyles with a great range in length 
and diameter and always with subterminal 
heads. The finer spicules tend to be found in 
the dermal spicule brushes of the sponge base; 
250-525 X 7—16.5/* (356 X 10.5/*). 
Micros clef, es. Large spirasters with stout, 
somewhat contort axes, at irregular intervals 
producing long branches which frequently have 
bifurcate tips; 36-50/x (42/*), shaft; 3 .0-5.0/* 
thick. 
DISCUSSION : Spirastrella aurivilli was referred 
to Cliona by de Laubenfels (1936:154) on the 
basis of Burton’s remarks on the three species 
of Spirastrella found on the Great Barrier Reef. 
Burton (1934) dearly stated that young stages 
of Spirastrella inconstans Dendy and specimens 
of Spirastrella aurivilli are capable of boring. 
At the same time he noted that the excavations 
were always of simple type and showed little re- 
semblance to the complex galleries of Cliona. 
In neither of the Palau specimens is there 
any trace of complex boring; the inhalant and 
exhalant tubes lead through simple straight 
channels in the coral. 
The distinctive microscleres and predomi- 
nantly boring habit of S. aurivilli serve to dif- 
ferentiate the sponge from the vast complex 
which Vosmaer ( 1911 ) includes in S. purpurea. 
DISTRIBUTION: Java Sea (Lindgren); Great 
Barrier Reef ( Burton ) . 
Spirastrella vagabunda Ridley 
RESTRICTED SYNONYMY: 
Spirastrella vagabunda Ridley, 1884, p. 468. 
Spirastrella vagabunda var. trincomaliensis 
Ridley, 1884. 
Spirastrella vagabunda Dendy, 1905, p. 122. 
Spirastrella vagabunda Wilson, 1925, p. 343. 
Anthosigmella vagabunda de Laubenfels, 
1954, p. 201, fig. 136, pi. ix, fig. b. 
OCCURRENCE: Sta. 12, 92, 124. 
DESCRIPTION: Specimens from Sta. 12 and 
92 are massive, digitate, with prominent oscules 
on the flattened tips of the branches and can 
be compared closely with de Laubenfels 5 speci- 
mens (1954: pi. ix, b). The third specimen 
(Sta. 124) Is a small subspherical sponge with 
a nodulose surface and prominent oscules scat- 
tered on the upper surface. It is probable that 
this represents only the apical portion of a 
branch of a sponge similar to the above. S. vag- 
abunda usually lies burled in the sand and the 
terminal portions of branches appear capable of 
constricting and detaching from the parent 
body, possibly serving as a means of asexual 
reproduction. 
Only a few facts about these specimens will 
be given to indicate how they differ from pre- 
viously described specimens. 
Two specimens (Sta. 12 and 92) conform 
closely in morphology to S. vagabunda as under- 
stood by most authors, having the dermal layer 
of outwardly directed small tylostyles, a dermal 
crust of spirasters, and lacking a second larger 
microsclere category. 
The megascleres of the third specimen (Sta. 
124) range from styles, to tylostyles (with 
terminal subterminal and polytylote heads), to 
tylostrongyles, and tend to be finer than the 
tylostyles of the other specimens. The cortex is 
without special organization, constituted of 
closely packed, interlacing spicules, the smaller 
types, styles and tylostyles, predominating. The 
