IQI5.] N. ANNANDALE: Indian Boring Sponges. 2% 
suggest that spicules of this peculiar type play an important part 
in the perforation of the compact outer layers of the shells in which 
the sponge constructs its burrows. 
Thoosa armata, Topsent. 
1887. Topsent, Arch. Zool. expérim. (2) V®, p. 81, pl. vii, fig. 
Q. 
1801. lide 0th OD: 570; 
1904. Id., ‘‘Spongiaires des Acores’’ Res. Camp. Sci. 
Monaco, fasc. XXI, p. 106, pl. xi, fig. 5. 
In preparations of Cliona vastifica from a shell of Malleus 
from the Andaman Is., I find, mingled with the spicules of that 
species, others of three types that agree well with those of Thoosa 
armata as described and figured by Topsent. They are nodular 
amphiasters, reduced oxyasters consisting of a pair of long horn- 
like spines arising from a minute centrum, and smooth, sharply 
pointed amphioxi. The spicules of other types figured by Topsent 
I have not found in this very imperfect specimen. 
As to the smooth amphioxi, they certainly do not belong to 
the Cliona and no trace of any other sponge but the Cliona and 
the Thoosa is present in some of my preparations. Topsent in his 
original description of T. avmata described amphioxi of the kind 
as an essential element in the spiculation of the species, but did not 
find them in the specimen from the Azores he described in Ig04. 
In my specimen, in parts of which they seem to be definitely as- 
sociated to form a skeletal structure, they are on an average 0°09 
mm. long and 0002 mm. broad at the thickest part. They are 
thus rather larger than in Topsent’s original example. 
Thoosa armata was described from a dried sponge in an oyster- 
shell from the Gaboon (West Africa), and has also been found in a 
dead coral in the Azores. It has not hitherto been known from 
the Indian Ocean. The extraordinary larva was described and 
figured by Topsent (op. cit.) in 1904. 
Thoosa hancocci, Topsent. 
1887. Topsent, Arch. Zool. expévim. (2) V’, p. 80, pl. vil, fig. 
12 
189I. hd.) tua. VX, pp: 577,.580- 
1898. Lindgren, Zool. Jahrb. (Syst. Abth.) XI, p. 320. 
1905. Topsent, Bull. Mus. Hist. Nat. Paris, XI, p. 94. 
Topsent and Lindgren have described this species as having 
spicules of three types, (a) tylostyles, (b) nodular amphiasters, 
and (c) slender amphiasters—Tindgren calls them spirasters—with 
lateral branches terminating in minute hooks. Topsent (of. cvt., 
1905) has also described a closely similar species without spicules 
of the last type (c), and founded for its reception the new 
genus Cliothosa. The only known species of this supposed genus 
(C. seuvati, Topsent) only differs from T. hancocct, apart from the 
