HEXACTINELLIDA. 17 
length. Sometimes these spicules are found among the diactin plenralia 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 80y, 
sharply bent, so as to form an angle of about 35° with the shaft. 
The autogastralia are completely spined hexactins, each ray being 140 « 12p. 
The intermedia. The oxyhexasters vary from 56 to 80pm in diameter; the 
commonest form is a holoxyhexaster, with principal rays 8-10p, 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°8y in diameter, with thick club-like primary rays, each ending in three 
prickles. 
The calycocomes (VI. 2e, e') average about 130 in diameter, the primary rays 
being trumpet-shaped, slender at their origin, and expanding gradually up to a disk- 
shaped capitulum; the secondary rays vary in number from three to six. Fig. 2¢ 
shows a calycocome with the terminal rays curving in at their extremities. Fig. 2f 
shows a portion of a larger calycocome, 210 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 in diameter, with short, slender, bifurcated 
primary rays, occur only rarely. 
The microdiscohexasters (VI. 2k) are 34 in diameter ; each primary ray ends in 
a sharp-pointed, conical capitulum. 
Dredged from 183 m. (100 fms.) off Coulman Island. 
AULOROSSELLA LEVIS. 
(Plate IL., 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. Root-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 toa 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 centimétres, of specimen A are as follows :—height, 20; root- 
tuft, 5 ; diameters in median horizontal plane, 12 x 10; orifice, 3°5 x 2; depth of 
central cavity, 11; thickness of wall, 3; height of cones, 1; length of pleuralia from 
surface of sponge, 3. 
