292 
Mr. H. J. Carter’s Contributions 
p. 267, pi. x. fig. 234) gave a representation of a quadri- 
radiate spicule, which is described as a specimen of a “ spicu- 
lated inequiangulated triradiate” (?spined inequiangulated 
quadriradiate) spicule, with “ cylindrical entirely spined 
radii” (? chiefly terminally spined), from u Dictyocylindrus 
Vickersii , Bk. MS.” In 1877, Mr. T. Higgin, F.L.S. 
(‘Annals,’ vol. xix. p. 296, pi. xiv. figs. 9, 10), represented 
the same kind of quadriradiate accompanied by an acuate 
spicule, which he found in small quantity on the piece of rock 
supporting his Higyinsia coralloides , which was brought from 
the West Indies. To this I alluded (‘Annals,’ 1876, vol. 
xviii. p. 391), from a mounted specimen kindly sent me by 
Mr. Higgin. In 1878 I found, in the late Dr. Bowerbank’s 
collection, a fragment of the sponge from which his figured 
spicule was probably obtained, with the following label on it, 
viz. “ Dictyocylindrus Vickersii , West Indies j” but as the 
vest of the* spiculation, together with the sponge itself, has 
never been described or illustrated, I now propose to do this 
from the fragment mentioned under Dr. Bowerbank^s name, 
which, so far as the characters of his genus Dictyocylindrus 
(Mon. Brit. Spong. vol. ii. p. 6, type D. hispidus, Bk.,= 
Rasjmlia , Schmidt) go, is well-chosen. 
Dictyocylindrus Vickersii , Bk. (PI. XXVII. figs. 5-8.) 
Fragment thick, triangular, wedge-shaped, composed of 
branched columnar structure, radiating from the inner angle, 
indicative of its having been broken out of a convex radiated 
mass (PI. XXVII. fig. 5) ; columns hollow, tubular, smooth 
within and rough without, wherein the spicules are implanted 
(fig. 8) ; branches terminating in lacinulated heads, which, in 
juxtaposition, form the convex or outer surface. Colour now 
black-brown. Texture loose, hollow, columnar, not fibrous. 
Surface of the columns setose from the projection of the long 
spicule (fig. 8, a). Wall of columns composed of dark brown 
areolar sarcode, charged, on the outside , with the spicules of 
the species. Spicules of four different forms, viz.:—1, long, 
setose, acuate, smooth, slightly curved, sharp-pointed, l-14tli 
by l-1800tli inch in its greatest diameter (fig. 6, a) ; 2, short, 
thick, acuate, smooth, slightly curved, towards the blunt end 
chiefly, sharp-pointed, l-45th by 1-900th inch (fig. 6, b) ; 
3, fine, acuate, irregularly undulating, smooth, slightly inflated 
in the centre, sharp-pointed, l-51st inch long and of extreme 
thinness (fig. 6, c) ) 4, echinating spicule, quadriradiate, arms 
cylindrical, more or less obtuse, for the most part equal in 
length, and radiating at nearly equal angles from each other, 
each spined, chiefly over the free extremity, about 1-360th 
