18 Records of the Indian Museum. [VOl.eet: 
Thoosa radiata, Topsent. Thoosa, investigatorts, nov. 
T. socialts, Carter. T. fischeri, Topsent. 
T. armata, ‘Topsent. T. laeviaster, nov. 
T. hancocci, Topsent. 
Of these I have not seen 7. socialis ! and T. fischeri,’ both of 
which are only known from Ceylon. 
It does not seem advisable at present to attempt to draw up 
a key tothe Indian species. One to all those known in I89gI is 
given by Topsent on pp. 585-586 of his paper cited after that date 
on p. 16, and no new species have been published since. Two are 
described in this paper. 
Thoosa investigatoris, sp. nov. 
(Plate i, figs. 5, 6). 
This is a species with megascleres in the form of pin-like tylo- 
styles and with three types of amphiasters as microscleres, vzz. (I) 
F1G. 3.—Spicules of Thoosa investigatoris. 
nodular amphiasters typical of the genus, (2) smooth amphiasters 
with horizontal branches ending in a circle of hooklets, and (3) 
much stouter smooth amphiasters without hooks or spines of any 
kind. 
General structure. —The sponge consists of a number of tubules 
which anastomose in one plane and swell out at intervals into not 
very clearly differentiated chambers of a flattened form and of 
irregullar outline. The whole structure is fragile and delicate, 
offering in this respect a strong contrast to Cliona annulifera, 
1 Carter, 1880, p. 56 (v. p. 2, footnote 3). 2 Topsent, 1891, p. 582 (v- p- 10). 
