REPORT ON THE MONAXONIDA. 37 



Skeleton. — The skeleton consists, as in the Rhizochalinse, of three kinds of network, 

 viz., (o) a dermal network of oxeote spicules lying immediately beneath a distinct, thin 

 dermal membrane. (6) A coarse, bast-like reticulation of very stout and dense fibres, 

 composed also of oxeote spicules, (c) A less dense reticulation of spiculo-fibre filling up 

 the centre of the sphere and giving support to the canal system ; in form and size the 

 spicules are the same as in the preceding. 



Spicules. — (a) Megasclera; oxea (PI. IX. fig. 3, a, h, c), size about 0"19 by O'OllS mm. 

 ij)) Microsclera, extremely abundant in the deeper sarcode in the form of small sigmata 

 (PI. IX. fig. 3, d), measuring 0-038 by 0-0032 mm. 



This common Shetland species is very poorly represented in the Challenger collection, 

 only two specimens of the body, a small one about 16 mm. in diameter, and a larger one 

 about 31 mm. in diameter, and a few detached fistuliB being present. The oxeote spicules 

 are somewhat shorter than usual, measuring 0-19 by O'Oll mm., while those of the type 

 measure 0-19 to 0-25 by 0-011 mm. 



Unfortunately, in the case of all the specimens, including the two bodies, there is 

 some slight doubt as to the exact locality where they were obtained. According to the 

 label on the outside of the bottle they were obtained " off Bermuda," whUe according to 

 a label inside the Ijottle, they were obtained " ofi" Bahia, shallow water." 



Probably the Rhizochalina (f) fihulata, described in four lines by Schmidt (Spong. 

 Meerb. Mexico, p. 7&) as a new species, from Barbados, 288 fathoms, and possessed of 

 numerous sigmata, is also referable to Oceana2:)ia robusta, although the description, 

 which is taken only from a fragment, is too short to make an identification practicable. 



Locality. — Bahia (?). 



Hcibitat. — Shetland Isles (Norman) ; ? Barbados (Schmidt) ; ? Bahia (Challenger). 



Subfamily 2. GELLiiKiE. 



1872. Gelliadae (pars), Gray, Ann. and Mag. Nat. Hist, ser. 4, voL ix. p. 449. 



1886. Gelliina, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, voL xviii p. 332. 



Megasclera all diactinal, oxea or strongyla. Microsclera present, viz., sigmata or 

 toxa. No rind nor fistulse. 



Genus Gellius, Gray (Pis. VIII., XIIL, XXVI.). 



1867. Gellius, Gray, Proc. ZooL Soc. Lond., p. 538. 



1867. Asychis, Gray, Proc. Zool. Soc. Lond., p. 539. 



1870. Desmacodes, Schmidt, Spong. Atlant. Gebiet., p. 5. 



1880. „ Vosmaer, Notes Leyden Mus., vol ii. p. 104. 



1882. Fihularia, imrs, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. ix. p. 282. 



1886. ? Fihulia, Carter, Ann. and Mag. Nat. Hist., ser. 5, vol. xvii. p. 51. 



Very little spongin present, never forming distinct fibres. 



Gray's original diagnosis runs as follows : — " Sponge massive, minutely hispid. 



