10 Records of the Indian Museum. [Vo.L. XI, 
left between the chambers) is about 0°425 mm. and the diameter 
o‘'r19gmm. ‘The papillae as a rule are borne only on the surface 
nearest the outer surface of the shell. The tubules connecting 
them with the chambers are longer than the horizontal tubules, 
but always much shorter than any diameter of the chambers. 
The chambers are by no means solid, their internal structure being 
coarsely reticulate. Delicate cellular diaphragms can sometimes 
be detected at or near one extremity of the connecting tubules. 
Papillae. I have been able to find only two kinds of papillae, 
corresponding to those styled ‘‘ poriferous’’ and ‘‘ mixed’’ by 
Topsent (1887). The largest poriferous papillae have a diameter 
of about 0225 mm. They are readily distinguished by the 
KG. 1.—Spicules of cliona annulifera. 
a. Gemmule-spicule. 
absence of a central orifice and by the absence or paucity (at 
any rate when they are contracted) of projecting spicules upon 
their surface, which is flat and horizontal. It is closed by a 
minutely perforate membrane on and in which the calcareous 
particles derived from the shell and carried out through the oscula 
lie in considerable numbers, being too large to enter the pores. 
In profile these papillae are flat and table-like, extending beyond 
their supporting tubules, which are cylindrical, for a considerable 
distance on either side; the free surface forms an acute angle with 
the projecting lateral margin. The mixed papillae are about the 
same size but have a central star-shaped or oval orifice of rela- 
tively large diameter. This is surrounded by a number of pori- 
