EURETE ERECTUM. 131 



are 20-76 ^ long and 1-3.5 /x thick at the base. They are usually attenuated 

 towards the end, more rarely of uniform thickness throughout. The end itself 

 is pointed, blunt, rounded or sUghtly thickened to a terminal "disc," which, 

 however, is always small, only rarely over 3 ^ in transverse diameter. The end- 

 rays are usually curved in an S-shaped manner, rather strongly concave to the 

 continuation of the axis of the shaft at the base, and \-ery slightly, in the opposite 

 direction, in their middle- and end-parts. These cm•^'atures, particularly the 

 basal, are subject to considerable variation. The breadth of the bunches formed 

 by the end-rays is 11-25 ix. The end-rays are uniformly covered by densely 

 crowded minute spines. The terminal "disc" is, when present, composed of 

 similar but slightly larger spines. 



The gastral scopules (Plate 30, fig. 15i; Plate 31, figs. 1, 6-12, 16a, 20, 23, 24i, 

 25-28) are 0.6-1.18 mm. long, and consist of a centrum, from one (the inner) end 

 of which arises a sunple shaft, and from the opposite (outer) a bunch of end-rays. 



The centrum is sometimes (Plate 31, fig. 27) rather clearly defined, some- 

 times it passes gradually into the shaft. It is 5-18 m long, 6.5-17 n broad, and 

 bears small backwardly directed spines, like those on the adjacent parts of the 

 shaft and the end-rays. An axial cross, composed of six axial threads regularly 

 arranged in the usual manner, can always be detected in the centrum. One of 

 these axial tlireads is long and continued in the axial thread of the shaft. The 

 one opposite this one is short, and terminates a considerable distance below the 

 distal end of the centrum, without giving off branches for the end-rays. The 

 other four axial threads are still shorter and equal among themselves. Some- 

 times four very sUght elevations arise from the sides of the centrum over them. 



The shaft is 0.52-1.05 mm. long, straight or slightly curved, and 3-11 fx 

 thick at the base, where it arises from the centrum. In some gastral scopules 

 it tapers toward the end, in its basal and middle-part, very gradually, in its distal 

 part rapidly. In most, however, its middle-part is cylindrical or thickened 

 and is 1-3 n, sometimes 13.5 m thicker than the base in transverse diameter. 

 The shaft terminates in a sharp point and is traversed throughout by an axial 

 thread. At the base it is covered with a greater or smaller number of minute 

 recurved spines, similar to those on the basal parts of the end-rays and on the 

 centrmn. Farther on it bears a few minute, isolated, vertical spines or is quite 

 smooth. A little distance below the end larger vertical spines are observed. 



Of end-rays there are usually four; in some gastral scopules, however, three, 

 five, or six have been observed. The end-rays are 75-133 m long, and 2-8 n 

 thick at the base. Generally the end-rays become thicker toward the distal end 

 (Plate 31, fig. 1) ; sometimes they are of uniform thickness throughout (Plate 31, 



