200 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
(iii.) Oxea (text-fig. 2, a)—A very few oxea occur, radially arranged, 
and traversing the sponge-wall from cortex to cortex, though they do not 
project from the surface. They are of almost the same diameter throughout 
their length, and their ends are bluntly pointed. They are quite straight or 
nearly so. 
C. Gastral cortex (Text-fig. 2, 7). 
The spicules of the gastral cortex are all triradiates and are considerably 
smaller than the dermal. They form a dense layer over the gastral ends of 
the chambers, and are arranged entirely without orientation. They do not 
show any definite distinction into basal and oral rays, but all three rays are 
frequently of slightly different length. The length of the rays is extremely 
variable ; but the diameter is fairly constant and equal for all the rays of one 
spicule. The gastral cortical spicules are much more slender than those of 
the dermal cortex, and their rays shorter. 
Spicular measurements (in millimetres). 
Basal rays. | Oral rays. | Apical rays. Diameter. 
Wermal triradiates ieee tee 0°38 to 0°42 | 0:33 to 0:40 LS | 0:035 to 0:04 
Subdermal quadriradiates ....| 0:23 to 0:26 | 0:23 to 0:25 | 0:5 to 0°65 | 0-035 to 0:345 
Subdermal triradiates (and | iy | 0:034 to 0:042 
subpastral)cneedeineras cinieese 05 to 0°65 | 0°18 to 0:28 | 
Gastral triradiates .......... O17 to 0°28 os | 0:02 
ORCA Means inca oe, hater ai eeke tera 1:2 to 13 - | qs 0:03 
The single specimen in the collection was obtained from the Harbour at 
Suez. 
Distribution. Red Sea. 
GRANTILLA HASTIFERA, sp.n. (PI. 19. figs. 3, 4.) 
The specimen (fig. 3) consists of a cylindrical syconoid person with a single 
apical osculum. The aboscular end is broken, and close to the osculum 
the proximal portion of a second sycon person joins on to the first; the 
second tube, however, is only a fragment. 
The specimen measures 22 mm. long by 9 mm. diameter at the widest part. 
The tubar skeleton is inarticulate, and is composed chiefly of prochiacts and 
sagittal triradiates, the oral rays of the latter being of unequal length. A 
number of radially disposed oxea also occur, whose outer ends project con- 
siderably from the sponge, and are “‘ semi-hastate,” 2. e. barbed on one side only. 
The canal-system is typically syconoid, the chambers being protected by a 
fairly well-developed dermal cortex, containing a dense layer of triradiates. 
