Dr. G. J. Hinde on Fossil Calcispongie. 197 
The sponge-walls are formed of anastomosing fibres, of the 
same character as those of V. D’Orbignyi; but instead of a 
single layer one sixth of a millim. in thickness, there is a 
continuous network 5 to 7 millim. in thickness, extending 
from the exterior to the surface of the central cloacal tube. 
The exterior is smooth, and exhibits closely arranged, approxi- 
mately circular apertures, which are in fact merely the inter- 
spaces between the network of the fibres. The examples do 
not show the interior surface of the cloaca. 
A dermal layer of relatively large spicules can be detected 
here and there on the surface; but i have not been able to 
obtain these detached; so far, however, as they can be ob- 
served by the aid of a simple lens, they appear to correspond 
in form, size, and position with the quadriradiate spicules of 
the exterior of V. D’Orbignyt. I have succeeded, however, 
in obtaining spicules of the interior fibre free from the matrix, 
and find them similar in all essential features to the filiform 
spicules of the preceding species. In some the basal ray is 
slightly longer and terminates acutely. The arrangement 
of the spicules in the fibre is also precisely similar to that 
already described in V. D’Orbignyt. This similarity in the 
spicular structure is of great interest when one considers the 
diversity in the form, size, and thickness of the wall in these 
two sponges. 
Horizon and Locality. Upper Greensand, Warminster, 
Wiltshire. 
Collection. British Museum of Natural History (Cunning- 
ton coll.). 
Corynella socialis, n. sp. (Pl: X. fig. 8.) 
Sponge compound, consisting of three or more individuals 
springing from a common cylindrical stem, or else growing 
by lateral buds. The base either widely expanded or con- 
tracted to a blunted point. The summits flat, wide, and 
obliquely truncate. The outer surface uneven, with short 
blunted projections. The typical example is 49 millim. in 
height and 43 millim. in its greatest width. The individual 
sponges are from 17 to 21 millim. in thickness. The walls 
vary from 5 to 10 millim. in thickness; and the aperture of 
the cloacal tube is 5 millim. in diameter. 
The outer surface exhibits apertures of uregular form 
bounded by the interlacing fibres. In one small part of the 
surface, spicules, apparently quadriradiate, could be detected. 
The fibre m one specimen was sufficiently firm to allow a 
thin microscopic section to be prepared from it. Examined 
by transmitted light the fibre presented the appearance of 
