REPORT ON THE TETRACTINELLIDA. 
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Genus 2. Discodermia. 
Discodermia (?) aspera, Carter. 
Discodermia aspera, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 147, pi. viii. fig. 49, 1880. 
Sponge . — Small, incrusting ; surface even ; oseules and pores (?). 
Spicules. — I. Megascleres. 1. Desma, of the usual form, epactines 0‘039 to 0'048 
mm. in diameter, axial rod 0‘05 to 0'06 mm. long, up to its point of bifurcation at the 
cladal origin covered with sharp spine-like tubercles. 2. Discotrisene, cladome margin 
denticulated, irregularly lobate, distal surface covered with sharp spines. O’ 12 to 0*2 mm. 
in diameter; rhabdome, conical strongylate, 0’024 to 0’036 mm. long. 
II. Microscleres. 3. Microxea, minutely spined, 0’058 mm. long. 4, Microstrongyle, 
fusiform, 0’016 mm. long. 
Colour. — Grey. Size, about 25 mm. in diameter. 
Habitat. — Gulf of Manaar; depth, under 65 fathoms. 
Remarks. — A prepared slide of this sponge was presented me by Dr. Carter ; I must 
confess I cannot trace the passage of the discotrisene into the desma. 
Discodermia calyx, Doderlein. 
CoralUstes poly discus {?), Carter, Ann. and Mag. Nat. Hist., ser. 4, vol. xviii. p. 464, 1876. 
Racodiscula, n. sp., Zittel, Abhandl. d. k. baier. Akad. d. Wiss., Bd. i. p. 151, 1878. 
Discodermia calyx, Doderlein, Zeitschr. f. wiss. Zool., Bd. xl. p. 62, pi. v., pi. vii. figs. 5, 6, 1884. 
Racodiscula asteroides, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. xv. p. 400, pi. xiv. figs. 
lla-lV, 1885. 
Sponge. — ^^^asiform or cylindrical, with a large central cup-like cavity, divided below 
into root-like lobes, or attached by an expanded base ; wall thick. Surface even. 
Oseules confined to the interior of the cup, more numerous at the bottom. Pores (?). 
Spicules. — I. Megascleres. 1. Desma, actines smooth, syzygial tubercles “ diffuse, 
not circumscribed nor globular.” 2. Discotrisene, rhabdome short, conical, pointed ; 
cladome thin, circular or trilobed, 0’35 mm. in diameter. 3. Pliyllotriwne, branched elk- 
horn-like, 0’64 mm. in diameter. 4. Oxea, fusiform, curved, 1’16 by O’Ol mm. 
II. Microscleres. 5. Microxea, fusiform, curved, minutely spined, 0’0465 by 0‘0028 
mm. 6. Microstrongyle, elliptical, compressed, minutely spined, 0'0127 to 0’0157 mm. 
long by 0’0042 mm. wide, and much less in thickness. 
Colour. — Yellowish-grey. Size, the typical specimen is 88 mm. in height by 69 mm. 
m maximum diameter; the cup-like cavity 44 mm. wide by 25 mm. broad and 63 mm. 
deep ; the wall is 9 mm. wide at the brim, but becomes thicker downwards. A second 
