R. W. He. ROW—REPORT ON THE SPONGES: CALCAREA. 211 
Fic, 7.—Oxea of Kebira uteoides, 
x 60. 
sparse layer of sagittal triradiates arranged 
tangentially. Gastral surface covered with a 
thin layer of subregular triradiates. Surface 
of the sponge smooth and not marked by ridges 
or depressions. There isa single osculum at the 
upper end—not guarded by any fringe or collar. 
The canal-system is typically leuconoid and 
possesses a series of shallow, but somewhat 
broad, subdermal cavities, from which inhalant 
canals lead to the chambers. From the 
chambers wide exhalant canals lead to the 
gastral cavity (PI. 20. fig. 3). 
I have been unable to distinguish the 
openings from the exterior to the subdermal 
spaces, but the arrangement of skeleton of the 
dermal cortex leads me to think that probably 
they are in the form of very numerous minute 
pores irregularly scattered over the surface of 
the sponge. No special pore areas were ob- 
served on the surface. 
The arrangement of the skeleton is shown in 
Pl. 20. fig. 9. 
The spicules are of two kinds, oxea and 
triradiates. 
(a) Oxea (Text-fig. 7). 
The oxea are extremely large, and occur in 
great quantities in the very thick dermal cortex 
covering the sponge. They are thickest in the 
middle, and gradually taper towards the ends. 
Their shape is more or less curved, according 
to the part of the body in which they occur, and 
the contour of which they follow, so that at the 
oscular end of the body, those of them which 
project into the oscular rim (fig. 76), which 
is very low, and not definitely marked off from 
the rest of the body, have their ends slightly 
bent in the reverse direction to the general 
curve of the spicule. 
They vary very greatly in length, being 
found in all stages of growth, so that the 
smallest observed specimen measures scarcely 
-2 mm. long, while all intermediate stages are 
