CALATHISCUS. 197 
Genus.—Catatrurscus, Sollas. 
1883. Quart. Journ. Geol. Soc., vol. xxxix, p. 546. 
Tubular, subcylindrical, or horn-shaped sponges ; the interior cloacal cavity 
extending nearly from the base. The ostia of the outer surface circular to oval, 
numerous, disposed either irregularly or sometimes in rows alternately; the ostia 
on the inner surface distinctly larger than those on the outside of the wall. 
Canals sinuous, interdigitating with each other in the substance of the wall. The 
skeletal meshwork very irregular ; some of the nodes are compact, whilst in others 
they are partially perforate but not regularly octahedral in character, as in 
Ventriculites. 
3. CaLaTHiscus vaRioLatus, Sollas. Plate XI, figs. 1, la—lc. 
1883. CatatTHiscus vaRIOLATUS, Sollas. Quart. Journ. Geol. Soc., vol. xxxix, 
p. 546, pl. xxi, figs. 17—20. 
The sponges are straight or shghtly sinuous, horn-shaped, irregularly swollen 
at intervals, the base bluntly pointed or with a slight expansion. ‘They range 
from 120 mm. to 160 mm. in height, and about 40 mm. in diameter in the upper 
portion. The walls are from 5 mm. to 6 mm. in thickness. The ostia of the 
outer surface are circular to oval in form, and vary from 1 mm. to nearly 2 mm. 
in diameter, whilst the interspaces between are about the same in width. The 
disposition of the ostia is masked by the weathering of the surface ; in some places 
they appear to be irregular whilst in others they are alternate in vertical rows. 
The ostia of the cloacal surface are about 2 mm. in diameter. The skeleton in 
some places forms subquadrate meshes with compact nodes, in others the nodes 
show perforations, and there is no definite arrangement. 
As in other siliceous sponges from the Inferior Oolite, the skeleton has been 
completely replaced by calcite. The specimens are not uncommon. 
Distribution.—Inferior Oolite. Parkinsoni-zone in the Cliff at Burton 
Bradstock, Dorset. (Coll. Rev. G. F. Whidborne.) 
oc 
