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THE VOYAGE OF H.M.S. CHALLENGER, 
tubercles. 2. DiscotrisBiies, those of the outermost layer circular, those beneath larger 
and with lobate divided margins ; outer surface minutely papillated, i.e., bearing short, 
conical spines. 
II. Microscleres. 3. Microstrongyle, ellipsoidal, .minutely spined, 0'0127 mm, in 
length. 
Habitat. — Gulf of Manaar ; depth, under 65 fathoms. 
Discodermia poly discus, Bocage. 
Discodermia polydiscus, Bocage, Journ. d. Sc. Math. phys. et nat. Lisbonne, p. 160, pi. xi. fig. 1, 
1869. 
Dactylocalyx polydiscus, Bowerhank, Proc. Zool. Soc. Lond., p. 96, pi. vi. figs. 9-14, 1869. 
Not Corallistes polydiscus, 0. Schmidt, Spong. Atlant. Gebiet., p. 24, pi. iii. figs. 8, 9, 1870. 
Discodermia polydiscus. Carter, Ann. and Mag. Nat. Hist., ser. 4, vol. xviiL p. 462, 1876. 
„ „ Zittel, Abhandl. d. k, baier. Akad, d. Wiss., Bd. i. p. 151, pi. i. fig. 7, 
1878. 
Not „ „ O. Schmidt, Spong. Meerb. Mexico, p. 22, 1879. 
Sponge. — Variable in form, irregularly cup-shaped, with a short pedicle and thick 
walls ; surface even. Oscules small, marginate, situated on the summit of slight 
elevations, or not dispersed. 
Spicules. — I. Megascleres. 1. Desma, epactines smooth, cylindrical, simple, or 
cladose, syzygial tubercles rounded, zygosis terminal. 2. Discotriaene, rhabdome conical, 
oxeate, cladome disciform, margin entire or lobate, about 0’3 mm. in diameter. 3. Oxea. 
II. Microscleres. 4. Microxea, fusiform, surface roughened, 0‘055 mm. in length. 5. 
Microstrongyle, O’Oll by 0 '003 mm. 
Colour. — When dry, light fawn-brown. 
Habitat. — Coast of Portugal (Bocage), near Cape St. Vincent (?) (Carter), and Island 
of St. Vincent, West Indies (Bowerbank). 
Discodermia (?) sinuosa. Carter. 
Discodermia sinuosa. Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vii. p. 372, pi. xviii. fig. 1, 
1881. 
Sponge. — Small, surface even. 
Spicules. — I. Megascleres. 1. Desma, of the usual tetracladine character. 2. Disco- 
trisenes, those most external, circular with a simple margin, those lying deeper, foliate 
with shallow denticulations, those deeper still, growing out into sinuous, branching, 
foliate lobes. 
II. Microsclere. 3. Microstrongyle, fusiform, centrotylote, minutely spined. 
Size, 13 mm. in diameter. 
Habitat. — Off Tuticorin, Gulf of Manaar ; Basse Rocks, south-east coast of Ceylon. 
