244 
THE VOYAGE OF H.M.S. CHALLENGER. 
Habitat. — Kors Fjord, Norway ; depth, 180 fathoms (Norman). Orkney Islands; 
depth, 35 fathoms; and Wick, Scotland (Bowerbank). Burrafirth, Unst, Shetland 
(Norman). 
Pachymatisma areolata, Bowerbank. 
Pachymatisma areolata, Bowerbank, Proc. Zool. Soc. Lond., p. 630, pi. xlviii., 1872. 
Sponge. — Massive, sessile ; surface uneven “ cloisone ” or raised into large anasto- 
mosing ridges which circumscribe shallow depressions. Oscules minute, numerous, 
congregated in deep areas within the depressions. Surface hispidated with somal and 
cortical oxeas. Cortex 0’95 mm. thick. 
Spicules. — I. Megascleres. 1. Somal rhabdus, both oxeate, strongylate, and oxy- 
strongylate, the oxea 22 ’3 mm. in length. 2. Cortical oxea. 3. Orthotrisene. 
II. Microscleres. 4. Sterraster, subspherical, O’ll mm. in diameter. 5. Spheraster, 
with short cylindrical actine's, 0’013 mm. in diameter. 6. Oxy aster or strongylaster, 
0“045 mm. in diameter. 7. Somal microstrongyle, 0'0065 mm. in length. 
Colour. — Cream-white in the dried state. Size, 175 mm. long by 94 mm. wide, 
by 69 mm. thick. 
Habitat. — Ked Sea. 
Subfamily II. Geodina. 
Genus 4. Geodia, Lamarck. 
The incurrent chones are furnished with cribriporal roofs. In the young sponge 
the oscule is the patent opening of a cloaca, into which the excurrent canals open by 
sphinctrate apertures ; in the adult the cloaca may persist, or become converted into a 
shallow depression, which is usually surrounded by a more or less sharply defined margin. 
Geodia gibberosa, Lamarck. 
Geodia gibberosa, Lamarck, M4m. Mus. Hist. Nat. Paris, vol. i. p. 333, 1815. 
„ „ Bowerbank {in part), Proc. Zool. Soc. Lond., p. 7, 1873. 
„ „ Sollas, Ann. and Mag. Nat. Hist., ser. 5, voL v. p. 241, 1880. 
non Geodia gibberosa, Duch. et Mich., Spong. Caraib., p. 105, pi. xxv. fig. 1, 1864. 
Sponge. — Subglobose, surface covered with slight tubercular elevations. A single 
large oscule bounded by a well-marked marginal edge, the patent opening of an exposed 
circular cloaca, over the floor of which numerous excurrent tubes open. 
Spicules. — I. Megascleres. 1. Somal oxea. 2. Cortical oxea. 3. Orthotrisene. 
