206 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
throughout their whole length. The basal ray is quite straight, but the paired 
rays are usually curved. The apical ray is much shorter and of less diameter 
than the facial rays. There is no orientation of the facial rays. 
Fig. 5.—Spicules of Lewcilla intermedia, all x60. 
C. Skeleton of the chamber-layer. 
(i.) Oxea (Text-fig. 5,¢).—The oxea are extremely long, and lie amidst 
the triradiates. They are arranged radially, with their distal ends projecting 
