270 
THE VOYAGE OF H.M.S. CHALLENGEE, 
Remarks. — The measurements were obtained from type-slides in the British Museum. 
The specimen is much worn. 
Isops (?) parasitica (Bowerbank). 
Geodia parasitica, Bowerbank, Proc. Zool. Soc. Bond., p. 328, pi. xxxi. figs. 12-15, 1873. 
Sponge. — Sessile, coating ; surface even or slightly nodose, smooth. 
Spicules. — I. Megascleres. 1. Oxea, 1'6 by 0'032 mm. (S.) to 1*85 by 0‘045 mm. 
(B.). 2. Orihotrisene, rhabdome 1'22 mm. long, cladi 0’31 mm. long (B.). 
II. Microscleres. 3. Sterraster, 0'08 mm. (S.) and 0'075 mm. in diameter (B.). 
4. Spheraster, centrum large, actines conical, numerous; centrum 0‘0105 mm. in 
diameter; total diameter 0’0169 mm. (B.). 5. Orthodragma, 0‘08 mm. long (S.). 
Colour. — Light cream-yellow in the dried state. Size, 6'1 mm. in thickness. 
Habitat. — Unknown. 
Remarks. — This species is founded on a fragment of a sponge, too incomplete for 
generic identification. The letter (B.) after the measurements of spicules indicates that 
they were obtained from Bowerbank’s description or figures, (S.) from measurements 
made by me on the type-slide in the British Museum. 
Isops inequalis (Bowerbank). 
Geodia inequalis, Bowerbank, Proc. Zool. Soc. Bond., p. 12, pL ii. figs. 18-23, 1873. 
Sponge. — Irregularly massive, sessile. 
Spicules. — I. Megascleres. 1. Strongyle, 1'837 mm. long. 2. Orihotrisene, rhabdome 
1'97 mm. long, cladi 0’127 mm. long. 
II. Microscleres. 3. Sterraster, oval. 4. Somal (f) chiaster, actines short, cylindri- 
cal, truncate, 0'0027 to 0’0056 mm. in diameter. 5. Subcortical {?) spheraster, actines 
conical, oxeate, numerous, 0‘032 mm. in diameter. 6. Choanosomal (?) oxyaster, actines 
large, conical, 0‘03 to 0’038 mm. in diameter. 
Colour. — Cream-white in its dried state. Size, 45 mm. in height by 35 mm. at the 
base and 19 mm. at the summit. 
Habitat. — Unknown. 
Remarks. — AU the measurements given above were obtained from Bowerbank’s figures 
and description. The single specimen which Bowerbank had under description is so 
much worn that it is impossible to be sure of its generic position. Circular holes are 
scattered all over the surface, and it is on the presumption that these were not covered 
with sieve-pores that the sponge has been assigned to Isops. 
