132 



EURETE ERECTUM. 



figs. 10-12) . Just below the distal end they measure 4-8 m 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 yu 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 ju 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 ;u 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 ^ broad. 



As examples the measurements of three gastral scopules of various dimen- 

 sions are tabulated below. 



