“Joyeuxia Belli*, sp. n.
Sponge attached, ovoid, with a thick rind enclosing a soft pulp; with short conical oscular, and long trumpet-shaped poral papillæ;. Surface finely pilose. Colour of surface yellow, of the rind whitish, and of the pith deep yellow.
Flagellated chambers 23 x 20 µ; diplodal.
Skeleton.—Cortical skeleton formed of layers of strongyles crossing each other at right angles. The walls of the oscular and poral papillæ supported by a layer of longitudinal strongyles. The surface of the sponge hirsute, with a fine pile of strongyles standing out at right angles or obliquely. Choanosome without spicules.
Spicules.—Slightly flexuous smooth strongyles 850 µ long, 10 µ in diameter at the ends, and 13 p, in diameter at the centre.
There is one adult specimen 5 cm. long, 3.5 cm. broad, and 3 cm. thick, with a deep groove on the under aspect, by which it was probably attached to a worm-tube or stem of a hydroid. There is also a small conical specimen, 6 mm. high, attached to a piece of rock.
I was at first disposed to regard this remarkable species as a member of a new genus, partly on account of its very thick rind, which is in places over a millimetre in thickness, and partly because of the highly specialized poral papillæ; but apart from these characters, the new form evidently shows the closest affinities to Joyeuxia. The three hitherto described species all have a rind enclosing a soft pulp, the latter being without or almost without a skeleton; then, too, the pulp is highly coloured. Joyeuxia tubulosa, Topsent, and J. ascidoides (Fristedt) have fistulæ, which, however, appear to be oscular. Two of the species, J. viridis and J. tubulosa, have strongyles; J. ascidioides has tyles and also chelæ. Accordingly Topsent places the genus near Desmacidon.
The poral papillæ attain a height of 1 to 1.2 cm.; they are expanded at the end.
The inconspicuous oscular papillæ are only about 4 mm. high and are tightly contracted.
Locality. Winter Quarters, 10-20 fath.
* Named in honour of Emeritus Professor F. J. Bell, of the Zoological Department of the Natural History Museum, and editor of the “Reports on the Natural History Collections” brought home by the ‘Discovery’ from the Antarctic.”
(Kirkpatrick, 1907)
