132 
EURETE ERECTUM. 
figs. 10-12) . Just below the distal end they measure 4-8 p in transverse diameter. 
In these measurements the fact finds its expression that the basally thin end-rays 
are distally thickened, whilst the basally stout ones are of uniform thickness 
throughout. The end-rays are destitute of axial threads and usually rather 
densely covered with minute recurved spines, which increase in size from the 
base, where they are about 0.7 p long (Plate 31 , fig. 27), to the end, where they are 
1.5-3 n long (Plate 31 , figs. 6-9, 26). The end of the end-ray is thickened to a 
tyle, 12-17 p in transverse diameter. This is particularly conspicuous in the 
end-rays which are thin at the base and thickened distally. The distal, apical 
face of the tyle is dome-shaped and usually quite smooth (Plate 31 , figs. 6-9). 
Its sides are densely covered with spines, directed obliquely downwards. The 
spines nearest its apex are small, farther down they rapidly increase in size, and 
the lowest attain 2 p or more in length. The spines of the tyle are, like those on 
the other parts of the end-ray, distinctly curved downwards. The end-rays are 
curved in an S-shaped manner, strongly, concave to the continuation of the axis 
of the shaft at the base, and slightly in the opposite direction in their distal 
and middle-parts. This second (outward) curvature is sometimes so light that 
the distal part of the end-ray appears straight. The degree of divergence of the 
end-rays is variable. The bunch formed by them is 60-102 p broad. • 
As examples the measurements of three gastral scopules of various dimen- 
sions are tabulated below. 
Total length p 
760 
920 
1180 
Breadth of the bunch of end-rays p 
64 
80 
62 
Shaft 
length p 
642 
789 
1050 
thickness 
in the middle p 
8.5 
9 
12 
at the base p 
6.5 
8 
9 
Centrum 
length p 
13 
18 
10 
thickness p 
12 
15 
13 
End-rays 
length p 
105 
113 
120 
thickness 
at the base p 
3.5 
5 
5 
just below the 
terminal tyle p 
4.5 
8 
5 
transverse diameter of the 
terminal tyle p 
15 
16 
12 
