ilie ' Challenger ' Monaxonida. 491 



distinct spiculo-fibre ; most compact just below the surface, 

 forming a cortical layer. Also with irregular tufts of projecting 

 spicules at the surface. Spicules : — (1) smooth acuates, rather 

 irregular in form, size "45 bj "0065 millim. ; (2) spinispirulee, 

 the largest slender, with five or six bends, length '044 millim. ; 

 more abundant are smaller ones, often with only one joint, 

 •0095 millim. long. 

 Locality. Station 162, Bass Straits, 38 fath. 



Spirastrella solida^ n. sp. 



Sessile, lobate : 3^ inches high by 2^ inches at base. 

 Light yellow. Very firm and hard, with much foreign 

 matter at base. Surface uneven, subglabrous in appearance. 

 Dermal membrane rather dense, heavily laden with spini- 

 spirulce. Oscula at tops of lobes. Pores scattered. Skeleton 

 a dense but irregular reticulation of spinulate spicules ; no 

 fibre; with loose radiating brushes of smaller spinulates at the 

 surface. Spicules : — (1) spinulates, with well- developed 

 subglobular heads, size in main skeleton *7 by '019 millim., 

 in dermal brushes '31 by '0094 millim. ; (2) spinispirulas, 

 [a) minute, slender, with about three bends, size '0126 by 

 •0025 millim., {h) a few much larger and relatively slenderer, 

 size '056 by -0025 millim. 



Locality. Station 208, Philippine Islands, 18 fath. 



Spirastrella papulosa, n. sp. 



Erect, sessile, conically lobose. Oscula at apex. Surface 

 covered with abundant low papillae. Height 6 inches. Grey. 

 Texture fairly firm, rather spongy. Dermal membrane thin, 

 loaded with spinispirulte, arranged so as to leave small pore- 

 bearing areas. Skeleton diifuse, fibres very slightly deve- 

 loped, especially dense just below surface; at the surface also 

 are irregular brushes of small spinulates. Spicules : — (1) 

 spinulates, with broadly oval heads, size '5 by •0157 millim. ; 

 (2) similar, but smaller (dermal), size "3 by •OOS millim. ; (3) 

 spinispirulffi, stout, with three or four bends and strong spines, 

 size (excluding spines) •OS by "009 millim. ; smaller ones 

 (young forms ?) also occur. 



Locality. Port Jackson, 30-35 fath. 



Genus Latrunculia (Bocage) . 



Massive, sessile, with acuate (or acerate ?) skeleton-spicules 

 and " sceptrella " * flesh-spicules forming typically a dense 



* For figure vide Carter, Ann. & Mag. Nat. Hist. ser. 5, vol. iii. pi. xxix. 

 fio-. 14, -whicli represents one modification of the "sceptrella." 



