R. W. H. ROW—REPORT ON THE SPONGES : NON-CALCAREA. lee 
The spicules are cylindrical, usualiy very slightly curved, and abruptly 
pointed at each end. They measure 0:11 mm. long in the secondary fibre, 
and slightly more (0-12 mm. to 0°14 mm.) in the main fibres. The average 
diameter is 0:0035 mm. 
- Locality. Agig Harbour. 
Distribution. Red Sea. 
RENIERA SPINOSELLA, n. sp. (Text-fig. 10.) 
This new species is represented by several specimens, none of which is 
large. All the specimens consist of an irregularly shaped mass of conical 
processes, each of which bears an osculum at the tup. There is, however, a 
very considerable variation in the amount of fusion which these processes 
.have undergone, as in some cases they are completely separate and in some 
they are almost completely fused, so that the whole specimen looks like an 
irregular mass with some slight rounded swellings over it. The largest 
specimen measures 55 mm. by 40 mm., and is 27 mm. high. The average 
diameter of the conical processes is 15 mm. 
All the specimens are growing amongst seaweed, and in some cases the 
seaweed has been enclosed within the sponge tissues. 
The surface of the sponge is typically covered with small processes scattered 
irregularly over the whole of the specimen. In the specimen in which they 
are developed to their greatest extent they are on the average 2 mm. high, 
and do not stand erect, but lie decumbent on the surface of the sponge. In 
other specimens they are shorter and more or less upright, but they are always 
very lax and easily bent. In one specimen these small processes are entirely 
absent and the surface quite smooth. The skeleton in this specimen is, 
however, exactly like that of the others, and it is quite impossible to separate 
this specimen from the others specifically. 
The surface is covered with a very delicate dermal membrane, which has 
no special skeleton. 
The oscula are confined to the summit of the large conical processes, 
each of these processes possessing a single osculum, which varies in diameter 
in different examples from 1 mm. to 2 mm. The pores could not be 
distin guished. 
The colour of the sponge is dirty grey. 
The texture is lax and very easily compressible, but not fragile, however, 
and not easily torn. 
Skeleton arrangement. 
The skeleton consists of a reticulation of spicules, with a few spicular 
fibres here and there. These primary fibres usually contain from three to 
five. rows of spicules, and in rare cases six or eight. The primary fibres 
themselves are very few in number, and are wholly absent from some parts 
