366 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
reticulate mass, from the upper surface and sides of which the free distal 
ends of the processes protrude. The free part of the processes is on the 
average about 20 mm. to 25 mm. in length, and from 10 mm. to 15 mm. in 
diameter. The largest specimen measures 60 mm. x50 mm. and is 65 mm. 
high. 
The colour in spirit is dark grey. 
The texture of the sponge is very brittle, and the whole sponge is easily 
crushed to powder. 
The surface is covered with small conuli, which are usually 1 mm. to 2 mm. 
high, though they may be as much as3 mm. They are asarule 3 mm. to 
4mm. apart. These conuli are produced by the occurrence beneath them of 
an accumulation of sand-grains, which frequently occur at the distal ends of 
the skeletal sand-fibres, but sometimes unconnected with them. These aggre- 
gations of sand-grains are connected with one another by sand-fibres, which 
form a series of ridges running between the conuli, and cause the whole 
surface of the sponge to appear reticulate. These dermal sand-fibres are 
frequently raised considerably above the level of the sponge surface, and 
connected with it by a delicate vertical membrane. 
The skeleton is wholly cf sand. There is no definite sand-cortex, but a 
dermal reticulation of sand-fibres, as stated above. Sand-grains are scattered 
throughout the cortex. 
The sand-fibres of the main skeleton are somewhat irregular in arrange- 
ment, and cannot be divided into main and secondary. They usually measure 
0:2 mm. in diameter, but sometimes, usually at a spot where a very large 
sand-grain has been engulfed, they measure much more, and may reach 
0:5 mm. in diameter. 
Locality. All the specimens were obtained from 5 fathoms of water in 
Suakin Harbour. 
Distribution. Red Sea, Australia. 
Eurysponeia, n. gen. (PI. 39. fig. 23; Pl. 41. figs. 27, 28.) 
Spongeliidee with a reticulate skeleton, in which primary radial fibres 
cored with foreign bodies and secondary connecting fibres without foreign 
bodies can be distinguished. 
This new genus has been necessitated by the presence in the collection of a 
sponge with Spongelid canal-system and eurypylous chambers, but with a 
skeleton exactly similar to that of Huspongia irregularis. 
HURYSPONGIA LACTEA, sp.n. (Pl. 89. fig. 23; Pl. 41. figs. 27, 28.) 
The species is represented by two large specimens, which form somewhat 
irregular, subspherical cushions, growing probably on mud. They are of 
