HOLASCELLA TARAXACUM. 
35 
axes is to be noted, two rays of such hexactines lying in one axis, and the ray of 
the pentactines which has no opposite being longer than the four rays lying in 
the two other axes. The rays are straight, conic, pointed or blunt, 120-180 n 
long and 3-8 tx thick at the base. With the exception of the base and the extreme 
tip, which are smooth, the rays are covered with spines, 1-1.5 n long. The distal 
spines are distinctly recurved (Plate 22, figs. 18, 19), the proximal ones arise 
nearly vertically. 
The rare oxyhexasters (Plate 21, figs. 1, 2, 9) are about 95 tx in diameter. 
Their equal and regularly arranged main-rays are straight, fairly Smooth, 19 n 
long, 4 ix thick at the base, and slightly attenuated towards the distal end. Each 
main-ray bears a terminal verticil of usually three end-rays, enclosing angles of 
about 45° with the continuation of the main-ray. The encl-rays are perfectly 
straight, 37 ix long, 2 tx thick at the base, conic, sharp-pointed, and covered with 
minute spines. 
The rare onychhexasters (Plate 22, figs. 27, 28) are 98-105 /x in diameter and 
have a thickened centre, 4-5 tx in diameter. The main-rays are regularly 
arranged, in the same spicule fairly equal, straight, on the whole cylindrical, 
8-11 ix long and 1.5-2. 3 tx thick. They bear from one to four, usually three, 
end-rays, and sometimes also one or a few irregular knob-like protuberances 
on their sides. The end-rays are 30-50 tx long and 0.6-1 tx thick at the base. 
Distally they taper gradually to about 0.3 tx. The end-rays arise nearly verti- 
cally from the main-ray and are curved in an S-shaped manner, their proximal 
part strongly concave towards the continuation of the main-ray, their distal 
part slightly in the opposite direction. This curvature is different in different 
end-rays and the degree of divergence of the chords of the end-rays from the 
continuation of the main-ray is variable. Each end-ray bears several terminal 
spines. These generally arise at nearly right angles, are curved, concave towards 
the centre of the spicule, slender, and 2-5 tx long. In view of the shape of the 
end-rays these onychhexasters might also be termed calicocomes. 
Of graphiocomes only a few centres (main-ray crosses) have been observed. 
The main-rays are regularly arranged, equal, 11-13 tx long and 2.5-4 tx thick. 
The abundant discohexasters (Plate 21, figs. 3-7, 10-13) are regularly spherical 
and measure 180-290 tx in total diameter. Their main-rays are regularly ar- 
ranged, in the same spicule equal, perfectly smooth, about 14 tx long, 3.5-5 tx 
thick in the middle, and thickened at both ends; proximally to the centre of the 
spicule, distally to a stout, lens-shaped, transverse disc from the margin and 
distal face of which the end-rays arise (Plate 21, fig. 10). The end-rays are 
