REPORT ON THE TETRACTINELLIDA. 
333 
0'003 mm. 6. Spiraster, very variable, passing into metasters and plesiasters, the latter 
into microxea ; total length of spiraster, 0’0237 mm., of a single actine of a plesiaster 
with four actines, 0*0 16 mm. The microxea (No. 4) is evidently derived from the 
spiraster. 
Habitat. — Florida; depth, 152 to 183 fathoms. Cuba; depth, 270 fathoms. 
Havanna; depth, 124 fathoms. 
Remarks. — The description of the spicules is taken from a small conical specimen, 
attached by a broad base, and labelled Discodermia polydiscus in Schmidt’s handwriting ; 
it was sent me by Professor Agassiz, who obtained it at a depth of 124 fathoms off 
Havanna. 
Racodiscula (?) sceptrellifera (Carter). 
Discodermia sceptrellifera, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vii. p. 373, pi. xviii. 
fig. 2, 1881. 
Sponge. — Small, about 6 mm. in diameter ; surface even. 
Spicules. — I. Megascleres. 1. Desma, of the usual character. 2. Discotrisene, passing 
from a circular form to one with three irregularly branching broad lobes. 
II. Microsclere. 3. Amphiaster, short, thick, sceptre-like. 
Coloi ir. — Y ello w. 
Habitat. — Gulf of Manaar ; depth, under 65 fathoms. 
Racodiscula spinispirulifera (Carter). 
Discodermia spinispirulifera, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 502, pi. viii. 
fig. 50, 1880. 
Sponge. — Small, about 6 mm. in diameter. 
Spicules. — I. Megascleres. 1. i)eswa,, syzygial tubercles subglobular. 2. Discotrisene, 
margin of the cladome circular or lacerated or irregularly branched. 
II. Microscleres. 3. Microxea, fusiform, curved, minutely spined, 0‘083 mm. long. 
4. Spiraster, 0'0125 mm. in length. 
Habitat. — Gulf of Manaar; depth, under 65 fathoms. 
Genus 4. Kaliapsis, Bowerbank. 
Tetracladidse which occur as thin incrusting plates, having the desmas of the base 
peculiarly modified ; the discotrisenes are tuberculated on the outer surface. The micro- 
sclere is a microstrongyle. 
