R. W. H. ROW—REPORT ON THE SPONGES : NON-CALCAREA. 37d 
very much closer together. From these conuli project the ends of the skeletal 
fibres, usually only very slightly, just so as to be apparent, but in some cases 
the fibre projects considerably, and occasionally branches outside the 
sponge. 
‘The colour in spirit is dark purple-brown. 
The texture of the sponge is firm, resistant, and not at all compressible. 
The skeleton consists of an irregularly branching fibre, the junctions 
between the fibres being somewhat few and quite irregular. This forms the 
chief difference between this species and Aplysina inflata, in which the 
skeleton is regularly reticulate. The skeletal fibre cannot be distinguished 
into main and secondary fibres, as there is no definite distinction of either 
thickness or direction to be made. Very great variations in thickness occur 
in the fibres, and they may measure anything up to 0°6 in diameter. Other 
fibres were found which did not exceed 0°05 mm. thick, as well as all inter- 
mediate sizes. The anastomoses between the fibres, and also connecting 
fibres, were very infrequent, and almost entirely absent from the more 
superficial parts of the sponge. 
The fibres are pithed, as is always the case in this genus, and the pith 
occupies usually about eight-tenths of the whole of the fibre. They are, 
however, entirely free from foreign bodies, as is the rest of the sponge. 
The canal-system of the sponge could not be clearly made out. In most 
parts of the specimen flagellated chambers were not distinguishable, and the 
sponge consisted of mesogloea, containing very large numbers of stellate cells, 
and perforated by an immense number of minute canals about 0-01 mm. in 
diameter. Where flagellated chambers do occur they are very small, not 
measuring more than 0-017 mm. in diameter, and they are by no means 
plentiful anywhere. 
No other details of the canal-system could be made out. 
Locality. “ Sponges from among coral collected from the shallows at Khor 
Dongola.” 
Distribution. Red Sea. 
APLYSINA RETICULATA, Lendenfeld. 
Synonymy :— 
1889. Aplysina reticulata, Lendenfeld (20). 
A single small specimen, consisting of a very irregular, and very thick, 
upright lamellar sponge, 60 mm. long by 30 mm. high. At its thickest point 
the lamella has a diameter of 12 mm., but this diminishes to almost nothing 
at the summit. The upper part of the sponge is cut into a number of lobes. 
The colour in spirit is dark violet. 
The skeleton-fibre is large, and possesses a very well-marked pith. It 
measures 01 mm. to 0°2 mm. in diameter, of which the pith constitutes +%. 
There are very few anastomoses between the fibres of the skeleton, especially 
