334 HYALONEMA (OONEMA) CRASSIPINUI-UM. 



pinules the distal part of the axis of tlie distal ray enclosed an angle of nearly 

 90° with its proximal part. The distal ray is (measured in the case of the 

 curved ones along the chord) 680-1130 yu long, most frequently 800-950 ;u, 

 20-35 /i thick at the base. Above it thickens considerably, and attains at its 

 point of maximum thickness, which lies a little above the middle of its length, 

 without the spines, a transverse diameter usually a little more than twice as 

 great as that of its base. At its distal end the ray is attenuated very abruptly 

 to a blunt point or is, exceptionally, rounded and dome-shaped. The proximal 

 part of the distal ray bears short and very stout, vertical, conical spines, which 

 extend quite down to its base. Farther on the spines become longer, curved, 

 concave towards the shaft and more and more inclined towards its distal end. 

 The longest spines attain a length of 20-40 ^i. The spines are usually regularly 

 arranged; only occasionally an irregular arrangement of those occupying the 

 concave side of curved distal rays is observed. The maximum diameter of the 

 distal ray, together with the spines, is 75-115 ix. The lateral rays are, at the 

 base, slightly thinner than the proximal end of the distal ray. They are nearly 

 cylindrical in their proximal and conical in their distal part, very blunt, G4- 

 150 n long, and spined. The spines are quite numerous, very stout, vertical, 

 conical, and generally up to about 6 m long. 



The small gastral pinules (Plate 92, figs. 5, 18, 21) are likewise all pentac- 

 tine. The distal ray is generally straight, 250-640 fi long, most frequently 

 500-640 At, and 12-28 m thick at the base. Above it thickens very consider- 

 ably and attains without the spines, at the point of maximum thickness, which 

 lies a little above the middle, a transverse diameter two to five times as great 

 as that of its base. Distally the ray is attenuated more gradually than in the 

 large gastral pinules, so that its end appears more slender. The distal ray is 

 covered with spines down to its base. The spines increase in length up to a 

 • point a little beyond the middle of the ray, where they are sometimes 20-30 fi 

 long. Beyond they again decrease in size. The lowest spines are, like those 

 of the larger gastral pinules, short, stout, conical, and vertical; l^ut as we pro- 

 ceed in a distal direction and the spines become longer, their tips curve upwards 

 more and more, and a short distance below the middle of the ray they pass, 

 often quite abruptly, into spines inclined and bent towards the end of the 

 ray to such an extent that their end-parts are very strongly inclined, parallel, 

 or even convergent. The distal part of the ray consequently has an appear- 

 ance very different from that of its proximal part, the former looking nearly 

 smooth, the latter bristling with large spines. The lateral rays are similar in 

 shape to those of the large gastral pinules, but only 50-125 ju long. 



