HYALONEMA (PRIONEMA) AGUJANUM. 
Distal ray Lateral rays 
maximum thick- 
ness, together 
length basal thickness with the. spines length 
be be Me 0 
form A 120-160 3-6 4-10 70-98 
var. lenuis 
form B 225-280 6-7 18-20 60-80 
var. lata 176-280 5-8 12-18 54-85 
Diactine, probably marginal pinules (Plate 78, fig. 3) have been observed 
Their distal ray 
is usually pointed, exceptionally reduced in length, and rounded and thickened 
at the end (Plate 78, fig. 3). 
directed, generally nearly straight spines. 
only in the preparations of var. tenuis, form A, and var. lata. 
It is covered with rather strongly inclined, distally 
The proximal ray is usually more or 
less spiny, and pointed or rounded at the end. A central tyle, the remnant of 
the (reduced) lateral rays, is always present. It is irregularly spherical or com- 
posed of four distinct lobes (ray-rudiments). Generally it bears several large 
spines which point obliquely upward and outward. 
The dimensions of the diactine pinules are:— 
Distal ray 
total length maximum 
we thickness, to- length of transverse 
basal gether with proximal diameter of 
length thickness the spines ray central tyle 
Me Ke be a Bb 
var. 
tenuis 400-610 200-290 5-10 17-20 190-320 16-21 
form A 
var. lata 410-490 167-260 6-9 26-33 160-260 12-23 
Pentactine and hexactine spicules with very slender rays have often been 
observed in the interior of var. lata. I consider these spicules, which are con- 
nected with the microhexactines by numerous transitional forms, as canalar 
pinules. In these spicules one ray is different from, usually longer, rarely shorter, 
than, the others. This differentiated ray, which is to be considered as the distal, 
bears oblique, distally directed spines. The other rays are also spiny, but their 
spines are much smaller and generally situated vertically. The ray to be con- 
sidered as the distal is 100-170 » long, 3.5-7 » thick at the base, and in its 
