R. W. H. ROW—REPORT ON THE SPONGES: CALCAREA. 207 
some way from the surface of the sponge. They are of somewhat peculiar 
shape, their greatest diameter occurring near the inner (gastral) end, which 
is abruptly pointed. The spicules taper gradually and uniformly to the 
distal end, which is very elongated and slender. 
(ii.) Triradiates (Text-fig. 5, c)—_The main portion of the skeleton of the 
chamber-layer is composed of irregularly scattered triradiates of rather large 
size, all the rays being of equal length and thickness. The inequality of the 
angles separating the rays, however, renders it always possible to distinguish 
the basal ray from the paired rays. The rays are all straight and somewhat 
abruptly pointed. 
Spicular measurements (in mm.). 
2 i aan renee : Diameter. 
| Basal ray. | Paired rays. Apical ray. Facial rays. | Apical ray. 
Subdermal quadriradiates .0:17 to 0-5 0°4 to 0°5 012 (0-015 to 0:017.0:015 to 0:016 
Gastral quadriradiates....0-1 to ou 0-1 to 0-11 0:07 to 0:08 = 0008 0-007 
All rays. Diameter. 
Dermal triradiates ...... 0-23 to 0:26 — 0:015 to 0-017 
pauidiatee of the chamber-|| 0.97 t5 0:5 sa 0:03 to 0-035 
VET ey ebshep so ssieve) avai aleve ( 
(OSE a aan n ne RIAN ae 10 to 380 — 0:05 to 0:06 
A considerable number of specimens of this sponge were obtained at Suez. 
Distribution. Red Sea. 
LEUCILLA CROSSLANDI, sp. n. 
The specimen in the collection is but a fragment, without osculum or place 
of attachment. It apparently belongs to a fairly simple sponge form. It is 
8 mm. long by 5 mm. broad at its widest part. 
The canal-system is typically leuconoid, with small spherical chambers 
irregularly scattered through the sponge-wall. 
The spicules are quadriradiates and triradiates. 
Skeleton arrangement. 
A. Dermal cortex. 
G.) Subdermal quadriradiates, of which there are two kinds :— 
(«) (Text-fig. 6,a). Very large sagittal quadriradiates, lying immediately 
below the dermal surface. Of the facial rays there is usually a short basal 
ray and longer paired rays, all three rays tapering uniformly to a sharp 
