REPORT ON THE TETRACTINELLIDA. 
251 
0'095 mm. (S,). 7. Somal spheraster, minute, centrum confluent with short, cylindrical 
rounded actines, 0’008 mm. in diameter. 8. Choanosomal oxyaster, centrum small, 
confluent with conical, minutely-spined or roughened actines, 0‘05 mm. in diameter. 
Colour. — Deep cream-yellow. Size, 213 mm. by 125 mm. by 50 mm. 
Habitat. — Norway, Vigten Island; depth, 100 fathoms (Bowerbank). Norway, Kors 
Fjord; depth, 180 fathoms (Norman). Near Hammerfest ; lat. 71° 12' N., long. 20° 30' 
E. ; depth, 135 fathoms (Vosmaer). 
Remarks. — The letter (B.) placed after a measurement indicates that it was taken from 
one of Bowerbank’s type-slides in the British Museum; (S.) that it was taken from a 
small sponge, 25 mm. in diameter, described by the author (loc. cit., vide supra). 
Geodia tuberculosa, Bowerbank. 
Geodia tuberculosa, Bowerbank, Proc. Zool. Soc. Bond., p. 626, pi. xlvi., 1872. 
Sponge. — Massive, sessile, somewhat cup-shaped, surface produced into tubercular 
prominences ; hispidated by somal and cortical oxeas. Oscules simple, small, numerous, 
collected in deep cavities. Cortex thin, from 0‘52 to 0'7 mm. in thickness. 
Spicules. — I. Megascleres. 1. Somal oxea, 2T by 0’037 mm. 2. Cortical oxea, 
curved, 0*405 mm. in length. 3. Orthotrisene, rhabdome 0‘044 mm. in diameter, cladi 
0*244 mm. long. 4. Protrisene, rhabdome 0*024 mm. in diameter, cladi 0*15 mm. long. 
5. Anatrisene, cladi 0*162 mm. long, chord 0*161 mm., sagitta 0*145 mm. 
II. Microscleres. 6. Sterraster, small. 7. Somal spheraster, centrum small, actines 
bacillary, truncate, diameter 0*015 mm. 8. Choanosomal spheraster, centrum well 
marked, actines cylindrical, thick, strongylate, densely spined, spines large, conical, 
diameter 0*061 mm. 9. Choanosomal strongylaster, centrum not enlarged, actines 
conical, slender, strongylate, diameter 0*032 mm. 
Colour. — (?). Size, 131 mm. in height by 100 mm. in maximum diameter. 
Habitat. — Mexico. 
Remarks. — The measurements of the spicules are taken from Bowerbank’s illus- 
trations. 
Section 2. Dirabdosa. 
Species possessing both cortical and somal oxeas, but neither anatrisenes nor pro- 
trisenes. 
