HBXACTINELLIDA. 17 



length. Sometimes these spicules are found among the diactin pleuralia projecting far 

 beyond the surface, but usually they are situated beneath the autodermal pentactins, 

 either near the surface or concealed amidst bundles of pleuralia. 



The anchor-like basalia (VI. 2a) have four thick, straight prongs, 560 x 80[i, 

 sharply bent, so as to form an angle of about 35° with the shaft. 



The autogastralia are completely spined hexactins, each ray being 140 x 12ja. 



The intermedia. The oxyhexasters vary from 56 to 80/a in diameter; the 

 commonest form is a holoxyhexaster, with principal rays S-lOjJi, each ending in four 

 straight, sharp-pointed secondary rays (VI. 2d) ; VI. 2d^ shows a variety with curved 

 secondary rays. Hemioxyhexasters in various grades occur, but are not so abundant 

 as the first kind ; monoxyhexasters are very rare. Fig. VI. 2d^ shows a micro - 

 oxyhexaster 22 ' 8ju. in diameter, with thick club-like primary rays, each ending in three 

 prickles. 



The calycocomes (VI. 2e, e^) average about 130/i, in diameter, the primary rays 

 being trumpet-shaped, slender at their origin, and expandiag gradually up to a disk- 

 shaped capitulum ; the secondary rays vary in number from three to six. Fig. 2g 

 shows a calycocome with the terminal rays curving in at their extremities. Fig. 2f 

 shows a portion of a larger calycocome, 210jU, in diameter, with a cylindrical capitulum 

 partly embraced by the bases of the secondary rays ; an axial canal extends about 

 half-way into each capitulum. 



Holodiscohexasters (VI. 2h), 94/i, in diameter, with short, slender, bifurcated 

 primary rays, occur only rarely. 



' The mierodiscohexasters (VI. 2k) are 34)u. in diameter ; each primary ray ends in 

 a sharp-pointed, conical capitulum. 



Dredged from 183 m. (100 fms.) off Coulman Island. 



AULOROSSELLA LEVIS. 



(Plate II., figs. 2, 3, and Plate VI., figs. 3-3h.) 



Sponge sack -shaped, with an oval orifice with thin unarmed edge. With conules 

 mostly tufted with pleuralia. Eoot-tuft formed of a compact mass of tufts of basalia. 

 Central cavity deep and spacious. Gastral wall smooth, showing sieve-like groups of 

 openings. Autodermalia pentactins and (rarely) stauractins, autogastralia pentactins, 

 and to a less extent hexactins. Intermedia including, among other kinds, numerous 

 hemioxyhexasters and monoxyhexasters. 



There are four specimens of this species, one large one of pale yellow colour (A) in 

 spirit, selected as the type, another (B) much larger, dried, and of dark brown colour, 

 and two small ones (C, D), in spirit. 



The dimensions, in centimetres, of specimen A are as follows :— height, 20 ; root- 

 tuft, 5 ; diameters in median horizontal plane, 12 x 10 ; orifice, S'S x 2 ; depth of 

 central cavity, 11 ; thickness of wall, 3 ; height of cones, 1 ; length of pleuralia from 

 surface of sponge, 3. 



