350 
HYALONEMA (OONEMA) SEQUOIA. 
Besides these spicules which will be described below, a number of others, 
chiefly amphidiscs (Plate 89 , fig. 15e) and pinules, were found in the sponge. 
Since, however, some of these kinds of spicules are very rare, and since the 
other, more frequent ones are identical with spicules of Hyalonema ( Hyalonema ) 
agassizi and Hyalonema ( Prionema ) fimbriatum trawled at the same Station 
and contained in the same jar, I consider them as foreign. 
The superficial pinules (Plate 86 , figs. 8, 13-26; Plate 87 , figs. 1-7; Plate 
88 , figs. 7-13; Plate 89 , fig. 15c) are nearly all pentactine, hexactine forms 
being very rare. These pinules are very unequal in size, the largest* attaining 
quite unusual dimensions. The distal ray is straight and 0.18-1.4 m m . long, 
most frequently about 0.9 mm. The length frequency-curve of the distal 
pinule-rays is simple, with a single elevation at 0.9 mm., which shows that these 
pinules form, in spite of their great dimensional differences, a simple, biometri- 
cally harmonious group. The distal ray is 5.5-55 ^ thick at the base, and 
together with the spines is 19-160 n thick at the thickest point. The maximum 
thickness is two to four times as great as the basal thickness. The point of 
maximum thickness lies rather far up, being usually three times as far from 
the base as from the tip of the ray. The distal ray ends in a terminal cone free 
from spines. This in the large pinules (Plate 87 , figs. 3a, 5, 7; Plate 88 , figs. 
12a, 13a) is broad, rather blunt, and traversed by a remarkably thick axial 
thread; in the smaller (Plate 88, figs. 7-10, 11a) it is either stout or slender, 
and not infrequently sharp-pointed (Plate 88, fig. 10). In the large pinules 
the distal ray is covered with spines quite down to its base (Plate 87 , fig. 3b; 
Plate 88, figs. 12b, 13b); in the smaller its basal part, for a short distance, is 
quite smooth (Plate 88, figs. 7-10, lib). The length of this smooth basal zone 
is, on the whole, in inverse proportion to the size of the spicule. The basal 
spines of the distal rays of the large pinules are short, broad, conic, sharp -pointed, 
and vertical. Distally they become more and more inclined towards the tip 
of the ray. At the same time they increase in length up to the point of maxi- 
mum thickness of the ray. From here up to the tip of the ray their length 
remains about the same. In typical large pinules the basal spines are up to 
7 /j. long, and 10-14 ^ broad at the base. The upper spines are equally thick but 
attain 35 m in length. Most of the inclined spines on the upper and middle- 
parts of the ray extend longitudinally, in planes passing through the axis of 
the distal ray. In a good many of the large pinules, however, irregularities 
occur in the position of the spines. Either the spines on part of the ray are all 
spirally twisted and directed obliquely to one side (Plate 87 , fig. 2), or there is, 
