204 MARINE BIOLOGY OF THE SUDANESE RED 
C. Gastral cortex. 
SEA. 
The spiculation of the gastral cortex is entirely made up, like that of the 
dermal cortex, of a layer of triradiates (text-fig. 4, c). 
Fig. 4.—Svicules of Grantessa glabra, all x 60. 
They are equiangular, 
and their rays are somewhat less in length than those of the dermal triradiates. 
They are also very much more slender, being not more than a fourth of that 
of the larger dermal triradiates. Their rays often show a slight variation in 
length, and are quite straight. They taper from the base to the apex. 
Spicular measurements (in mm.). 
4 
Basal ray. Oral rays. Diameter. 
Wermialitrinadiatess ses. 4e eee een 0:5 to 0'7 0:5 to 0:65 0:04 to 0:065 | 
Gastral triradiates ............00004. 0-4 to 0-5 0-015 
‘WV bane Tae HNKESS 5 ooo con ooo sco anoe 0-75to08 | O04 to 05 0:07 to 0:09 
(SRA nA a sc: OA ae ene eatrene | ua ae A | 1:0 to 1:1 0:05 to 0:06 
