195. | N. ANNANDALE: Indian Boring Sponges. 3 
of microscleres present also, but never 
spiny diactinial spicules of relatively 
large size and of polyactinial origin .. Thoosa. 
B. [Macroscleres normal tylostyli, occurring as 
in Thoosa. The only microscleres am- 
phiasters consisting of a cylindrical stem 
bearing at the ends a circle of relatively 
long horizontal branches which are in- 
flated at the tip or terminate in several 
minute hooks; the whole spicule smooth 
and slender ‘ a .. Clhothosa. | 
C. Macroscleres entirely absent; their place 
taken in the external papillae, but not in 
the galleries, by relatively large spiny or 
nodular diactinial spicules some of which 
reveal their polyactinial origin by being 
definitely bent or geniculate in the mid- 
dle, or even by bearing extra rays, com- 
plete or rudimentary, in this position. 
Amphiasters like the typical ones of 
Thoosa but with the lateral bosses far 
removed from the extremities, which are 
not always capitate aa .. Alectona. 
Genus Cliona, Grant. 
1826. Cliona, Grant, Edinb. Phil. Journ. I, p. 78. 
1849. - Hancock, Ann. Mag. Sct. Nat. (2) III, p. 305. 
1888- = Topsent, Arch. Zool. expérim. (2) V®, p. 76. 
1891. sé Id., tbid,, IX, p. 556. 
1900. a T¢.5, totd (3) VIL, py 32. 
1900. Dyscliona, Kirkpatrick, Ann. Mag. Nat. Hist. (7) VI, 
- 353: - 
1907. Cliona, Topsent, Arch. Zool. expérim. (4) VU, p. xvii. 
Further references will be found in Topsent’s papers, which 
are essential for a study of the Clionid genera and particularly for 
that of Cliona. In 1891 he arranged the species in six groups as 
follows :-—~ 
Group I. Spicules including tylostyles, diactinial macroscle- 
res and spirasters (microscleres). 
Group II. Spicules consisting of tylostyles and diactinial 
macroscleres only. 
Group III. Spicules consisting of tylostyles and microscleres 
only. 
Group IV. Spicules consisting of amphioxi and microscleres 
only. 
Group V. Spicules consisting of tylostyles only. 
Group VI. Spicules consisting of amphioxi only. 
