306 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
unable to penetrate the inner part and dies off. Many shells show that they 
were attacked badly some time previously and have recovered.” 
Distribution. Red Sea, Great Britain, Norway, Denmark, France,. Mediter- 
ranean, Atlantic coasts of America, south coasts of Australia, New Guinea. 
Sub-Order SIGMATOTETRAXONIDA, Hentschel * (15). 
Tetraxonida in which the typical microsclere is a sigma or some form 
derived from it. True astrose microscleres are never found. 
Family TETILLID 4. 
Sigmatotetraxonida in which there are well-developed protriznes and a 
usually strongly radiate skeleton. 
TETILLA POCULIFERA, Dendy. 
Synonymy :— 
1905. TZetilla poculifera, Dendy (11). 
Six subspherical specimens of this sponge were obtained. They are all 
somewhat small, the largest being 26 mm. in diameter. They agree closely 
in all points with Professor Dendy’s specimens from Ceylon, but the small 
oxea which occur throughout the choanosome are even more numerous than 
in his specimens, so that a section looks quite dark when examined owing to 
their enormous numbers. 
All the specimens were obtained from Tella Tella Kebira. 
Distribution. Red Sea, Ceylon. 
PARATETILLA ECCENTRICA, n. sp. (PI. 35. fig. 1, Pl. 36. fig. 8; Text- 
figs. 5, 6, 7.) 
This species is represented by a single small specimen, of nearly spherical 
shape, but with the basal part missing. The surface of the sponge is very 
minutely bispid, the projecting spicules being few and small. 
The specimen measures 21 mm. in diameter. 
The oscula are irregularly scattered over the surface of the sponge, about 
a dozen in number, and measuring 1-2 mm. in diameter. An oscular 
membrane is usually visible, and the sides of the osculum are frequently 
sparsely coated with sand-grains. The pores were indistinguishable. 
* Hentschel (15) gives no definite diagnosis to this sub-order, save to say that it comprises 
the Sigmatophora and Sigmatomonaxonellida of Dendy’s classification (11). The above 
diagnosis, therefore, has been formulated to correspond with his diagnosis of the sub-order 
Astrotetraxonida. 
