APPENDIX I. 
OMISSA. 
Thenea muricata (Bowerbank) (p. 95). 
Tisiphonia agaridformis, Schulze, Eeport on the Sponges dredged by the “Knight Errant,” 
Proc. Koy. Soc. Edin., p. 708, 1882. 
Schulze records this species from Station 92, “ Knight Errant,” depth, 275 fathoms. 
Thenea intermedia (p. 97). 
Tisiphonia agaridformis, C. Keller, Archiv f. mikrosk. Anat., vol. xviii. p. 271, 1880. 
Keller mentions the occurrence of this species in the Gulf of Naples, on muddy 
ground. 
I 
Characella pachastrelloides (Carter) (omitted from p. 101). 
Stelletta pachastrelloides, Carter, Ann. and Mag. Kat. Hist., ser. 4, vol. xviii. p. 403, pi. xv. fig. 40. 
Sponge. — Massive, free or attached, surface asperous owing to the projection of oxeate 
spicules ; oscules single or in groups, irregularly distributed ; pores ‘‘ tympanising the 
interstices between the projecting spicules.” 
Spicides. — I. Megascleres. 1. Oxea, 3‘66 by O’l to 4‘62 by 0'084 mm. 2. Ortho- 
triaene, rhabdome 0‘85 by 0*07 mm., cladi 0*49 mm. long. 3. Anatrisene, rhabdome 3 ’66 
by 0'021 to 6‘64 mm. long, cladi 0‘17 by 0’021 mm. 
II. Microscleres. 4. Microxea, 0’245 by 0’0064 mm. 5. Microxea, centrotylote or 
not, curved or suddenly bent in the middle, 0‘0465 b}^ 0'0085 mm. 6. Oxyaster, actines 
from six to seven in number, minutely spined towards the ends, 0’017 mm. in diameter. 
7. Amphiaster, passing into a spiraster, 0'013 mm. in length. 
Colour. — Cream-yellow. 
Habitat. — Atlantic Ocean, near Cape St. Vincent; depth, 374 fathoms (Station 25, 
“Porcupine” expedition, 1870). 
