318 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
of the sponge. They run quite regularly radially in the sponge, and fre- 
quently pass out into the small processes above described. 
The rest of the skeleton is wholly unispicular, and the 
sides of the mesh usually consist each of a single spicule. 
The reticulation thus formed is quite regular in most parts 
—— 
of the specimen, but at the points of fusion of the large 
processes of which the sponge is composed they become 
more or less irregular. 
Spicules. 
The only spicules which occur in this species are oxea ; 
they are sometimes slightly curved, but usually quite 
| straight and cylindrical. They are usually tapering 
| throughout their length, but occasionally spicules may be 
found of the same diameter for the greater part of their 
length, and are abruptly pointed at each end. They 
! measure 0°13 mm. in length and 0:005 mm. in diameter. 
Fig. 10.— Reniera 
spinosella, Spi- 
cules, x 500. 
Locality. The whole of the specimens were obtained in 
Suez Docks, “from beneath a floating stage, which had 
been in the docks for several years.” 
Distribution. Red Sea. 
RENIERA sp. 
A small, somewhat triangular fragment, apparently broken off from a 
lamellar sponge. The fragment is 5 mm. thick, and measures 25 mm. long 
by 15 mm. wide at the widest part. The broken surface extends around two 
sides of the triangle, the third (and shortest) side being the external edge 
of the sponge. 
The skeleton arrangement is very regular, consisting of a rectangular mesh- 
work, each of the sides of each mesh being composed typically of a single 
spicule, so that the diameter of the mesh is the same as the length of the 
spicules. 
A few spicular fibres can be distinguished here and there in the sponge, 
but they do not seem to lie in any particular direction, and they very 
rarely indeed contain more than two rows of spicules, and never more than 
three. 
The dermal membrane is supported by a reticulation of spicules, but neither 
the size of the mesh nor that of the spicules differs at all from those of the 
main skeleton. 
The spicules are oxea, and as a rule quite straight, though a few were seen 
