334 
HYALONEMA (OONEMA) CRASSIPINULUM. 
pinules the distal part of the axis of the distal ray enclosed an angle of nearly 
90° with its proximal part. The distal ray is (measured in the case of the 
curved ones along the chord) 680-1130 n long, most frequently 800-950 n, 
20-35 n thick at the base. Above it thickens considerably, and attains at its 
point of maximum thickness, which lies a little above the middle of its length, 
without the spines, a transverse diameter usually a little more than twice as 
great as that of its base. At its distal end the ray is attenuated very abruptly 
to a blunt point or is, exceptionally, rounded and dome-shaped. The proximal 
part of the distal ray bears short and very stout, vertical, conical spines, which 
extend quite down to its base. Farther on the spines become longer, curved, 
concave towards the shaft and more and more inclined towards its distal end. 
The longest spines attain a length of 20-40 /x. The spines are usually regularly 
arranged; only occasionally an irregular arrangement of those occupying the 
concave side of curved distal rays is observed. The maximum diameter of the 
distal ray, together with the spines, is 75-115 m- The lateral rays are, at the 
base, slightly thinner than the proximal end of the distal ray. They are nearly 
cylindrical in their proximal and conical in their distal part, very blunt, 64- 
150 n long, and spinecl. The spines are quite numerous, very stout, vertical, 
conical, and generally up to about 6 n long. 
The small gastral pinules (Plate 92 , figs. 5, 18, 21) are likewise all pentac- 
tine. The distal ray is generally straight, 250-640 /z long, most frequently 
500-640 ii, and 12-28 n thick at the base. Above it thickens very consider- 
ably and attains without the spines, at the point of maximum thickness, which 
lies a little above the middle, a transverse diameter two to five times as great 
as that of its base. Distally the ray is attenuated more gradually than in the 
large gastral pinules, so that its end appears more slender. The distal ray is 
covered with spines down to its base. The spines increase in length up to a 
point a little beyond the middle of the ray, where they are sometimes 20-30 /x 
long. Beyond they again decrease in size. The lowest spines are, like those 
of the larger gastral pinules, short, stout, conical, and vertical; but as we pro- 
ceed in a distal direction and the spines become longer, their tips curve upwards 
more and more, and a short distance below the middle of the ray they pass, 
often quite abruptly, into spines inclined and bent towards the end of the 
ray to such an extent that their end-parts are very strongly inclined, parallel, 
or even convergent. The distal part of the ray consequently has an appear- 
ance very different from that of its proximal part, the former looking nearly 
smooth, the latter bristling with large spines. The lateral rays are similar in 
shape to those of the large gastral pinules, but only 50-125 m long. 
