412 COLLECTIONS FROM MELANESIA. 



wide apart, vertical to surface, 3 to 8 spicules broad ; secondaries 

 at less intervals, 3 to 6 spicules broad ; the interstices occupied by 

 much irregular 1- or 2-serial network. Dermal skeleton of stout 

 spiculo-fibre, similar to that of main skeleton ; the spicules 3- to 

 8-serial, forming a network of subrectangular meshes, - 4 to '7 millim. 

 wide, enclosing detached or loosely aggregated spicules. Sarcode very 

 pale yellowish brown, slightly granular. Spicules smooth acerate, 

 slightly and gradually curved, tapering to sharp points from about 

 three diameters from ends (varieties occur having one end tapering 

 more or less to a blunt rounded extremity, or with one end rounded 

 and as stout as the middle of the spicule, thus becoming truly 

 acuate); size "2 by '0127 millim. 



Bab. Port Darwin, 7 fms. ; bottom sand. 



This species is perhaps allied to Reniera aquceductv.s. It differs 

 from that species in the anastomosing and externally spinous tubes 

 and in the superior diameter of the spicule, which does not exceed 

 •0095 millim. in that species. The specimen forms a low hedge-like 

 series of anastomosing tubes, which are almost horizontal at their 

 lower ends ; maximum height of colony 55 millim. (24- inches), 

 maximum lateral extent 100 millim. (4 inches). It has a remarkahlo 

 external resemblance to a form of the Chalinid, Tuba acajiiihensis, 

 Carter. 



46. Pellina aliformis. (Plate XXXIX. fig. ; 

 Plate XLI. fig. iv.) 



Erect, with slender pedicle ; expanding into one or more wing-like 

 lobes, 4 to G millim. thick, 14 to 20 millim. in greatest width ; the 

 free edges looking upwards and downwards respectively and the apex 

 directed horizontally. Surface more or less roughened (especially 

 on the flat surface of the lobes) by the conuli, about *6 millim. 

 apart, which enclose the ends of the primary skeleton-fibres ; the 

 margins of the lobes, and sometimes their sides, are covered by a 

 glabrous semitransparent membrane. Vents few, suboval, 2 millim. 

 in greatest diameter, with thin membranous margins, generally 

 placed on the edges of the lobes; their cavity oblique, entered by 

 numerous excretory canals. Texture in spirit brittle, slightly 

 elastic ; colour very pale brown. 



Main skeleton — spiculo-fibres loose, no perceptible horny uniting 

 substance ; primary fibres approximately vertical to surface, •(> to 

 •85 millim. apart, 8 to 10 spicules broad ; secondary fibres at 

 various angles to primaries, at some distance apart, about 5 spicules 

 broad. Dermal skeleton thick, formed of very loose spicular tracts 

 of various sizes, crossing each other at various angles, leaving small 

 spaces between them. Sarcode rather granular, pale brown. Spicules 

 smooth acerpte, slightly curved, tapering to sharp points from near 

 centre ; size -5 by "025 millim. 



Hab. Port Darwin, 8-12 fms. ; bottom sand and mud. 



Represented by one whole specimen and one fragment, in spirit. 

 The former 33 millim. high by about the same wide, and formed 



