to our Knowledge of the Spongida. 
353 
Corticium Wallichii , Cart. (1874). 
(PI. XXIX. figs. 5-9.) 
Minute, amorphous, laminiform. Colour that of dried sar- 
code, i. e. yellowish. Texture like dried sarcode—that is, 
gum-like. Pores, vents, and internal structure not visible, 
from the minuteness and dryness of the specimens. Spicules 
of two kinds, viz.:—1, skeleton-, large, acerate, curved, tuber- 
cled throughout in twelve longitudinal lines (PI. XXIX. 
fig. 5); tubercles alternate in adjoining rows, constricted in 
the centre, expanded at the free ends, the latter circular and 
convex (fig. 5, a a a), extended over the extremities of the 
spicule so as to give them an obtuse irregular form. Central 
canal bent angularly in the middle towards the convexity of 
the spicule, undulating afterwards towards the extremities 
(fig. 5, b) 7 l-31st by l-200th inch in its greatest diameters, 
including the tubercles—or the same spicule in an earlier 
stage of development, without tubercles, and with an angular 
projection in the centre of the convexity (fig. 6), opposite the 
bend in the central canal (fig. 6, a) ; 2, flesh-spicule, scep- 
trelliform (fig. 7), consisting of a straight shaft, abruptly 
pointed at each end, and microspined throughout, except in 
the middle (fig. 8, a), provided with two circles of horizontal 
rays, separate from each other, and a little nearer one end of 
the shaft than the other (fig. 8, h b), rays eight or less in 
number, straight, smooth, capitate, each terminated by a glo¬ 
bular inflation, shaft l-1000th inch long, circle of rays 
1-3000th inch in diameter (fig. 9,«, bb). Skeleton-spicule in 
different degrees of development, mixed together with the 
flesh-spicule in the sarcode. Size that of the excavated cavity 
in the piece of Stylaster where it was found, viz. about 1-18th 
inch in diameter. 
Hab. Marine, in the cavities of ? Cliona mucronata in dead 
old Stylaster sanguineus (coral). 
Loc. South seas. 
Obs. Examined in the dried state. In 1864 Dr. Bowerbank 
(Mon. Brit. Sp. vol. i. p. 270, pi. xi. fig. 244) gave a figure 
of the skeleton-spicule of this sponge that had been frequently 
found in the washings of Oculina rosea — Stylaster sanguineus, 
from the South Seas, noting that the sponge itself from which 
it came had “never been determined.” In 1871 Dr. G. C. 
Wallich kindly sent me some of his “ dredgings ” on the 
Agulhas Shoal, Cape of Good Hope, made in 1857 ; and 
among these I found and mounted a spicule of this kind, from 
which the description and figure were taken (‘ Annals,’ 1874, 
vol. xiv. p. 252, pi. xv. fig. 46), when I proposed for the 
Ann, & Mag . N. Hist. Ser. 5, Vol. iii, 25 
