148 



ECHINOIDEA. I. 



of them the spines are somewhat shorter than the diameter of the test, in some specimens even only 

 half so long. In conformity to the size of the tubercles the spines on the ambulacral areas are a little 

 shorter than those of the interambulacral areas. The actinal spines are blunt, a little flat, but not 

 widened at the point. In the more long-spined specimens the primary spines decrease only little in 

 length towards the apical area, in the specimens with shorter spines those at the ambitus are con- 

 siderably longer than the others. 



The pedicellarise are most frequently rather few, especially the globiferous and tridentate ones, 

 sometimes one or the other, or even both of these forms are quite wanting in large specimens. The 

 globiferous pedicellarise (PI. XVIII. Figs. 9, n) have commonly 34 teeth on either side of the blade; 

 the number is, however, varying from 2 5 teeth, and there is often an unequal number on the two 

 sides. The edges of the blade are commonly connected by some cross-beams, but sometimes they are 

 not connected at all, as in the type specimen (Fig. 9). That this feature can be of no greater import- 

 ance here, so that it might be used as a specific character, is sure enough, as in the same pedicellaria 

 one valve may be found with the edges of the blade connected by cross-beams, while in the others 

 the edges are not connected. Generally, however, the edges are connected, as shown in Fig. n. The 

 basal part may be finely rounded, or with a single indentation in the edge; the apophysis is most 

 commonly a little serrate in the edge. In the type specimen the upper end of the apophysis has a 

 peculiar form which I have not found quite similar in other specimens. 



The tridentate pedicellarise (PI. XVIII. Figs. 23, 25. PI. XIX. Figs. 34, 38. PI. XX. Fig. i. PI. XXI. 

 Fig. 20) are very different from those of the other c/imus-species. The valves are broad , rather flat, 

 without mesh-work at the bottom (except just at the end of the apophysis); they are full of holes 

 regularly arranged in beautiful arcs. The edges are often somewhat bent inward in the lower part, 

 where the valves are apart (PI. XVIII. Fig. 23); in the outer part, where the valves join, the edge is 

 rather coarsely sinuate. The edges are thick, set with transverse series of small teeth; in the outer 

 part these small teeth are numerous and not placed in transverse series (PI. XXI. Fig. 20). Generally 

 these pedicellarise are rather large, up to 2'5 mm , but quite small forms may also be found, as the one 

 figured on PI. XIX. Fig. 38. -- Danielsseu has not found the tridentate pedicellarise in the type 

 specimen; the figure with regard to which Koehler supposes that it might be a tridentate pedicellaria 

 (Fig. 9), is a globiferous one, and even a tolerably good figure (Koehler has found no globiferous 

 pedicellarise in his specimens). The tridentate pedicellarise are, however, also found in the type 

 specimen; I have found a few ones, all rather small; on PI. XIX. Fig. 34 is figured a valve of one of 

 these pedicellarise. They are broad and flat as in the other specimens, only the edge is not curved 

 inward in the lower part; this feature, however, is of no great importance, as in the same specimen 

 some pedicellarise may be found with inward bent, others with straight edge. As such broad, triden- 

 tate pedicellarise are not found in any other Echinus-species , they are of great importance for the 

 determination of this species. Unfortunately they are not rarely wanting. 



The ophicephalous pedicellarise (PI. XIX. Fig. 16) are generally very sinuate in the edge; the 

 mesh-work in the blade is not much developed. In some specimens together with this common form 

 another larger, more lengthened form is found with many serrations in the edge and well developed 

 mesh-work in the blade (PI. XX. Fig. 27); they may be almost as large as the tridentate pedicellariae. 



