ECHINOIDEA. II. 



135 



they are ratlier large (ca. o-5""" leugth of head), and the thick, probably glandular,' dark pigmeuted 

 skin makes theni ver\' conspicuous objects. 



The rostrate pedicellariæ (PI. XVII. Figs. 17, 40, 50) have very short valves, joining in the 

 outer half (or more) of the blade. In faet, it is rather difficult to recognize the rostrate type of pedi- 

 cellariæ in this form, but a comparison with the corresponding form in the other species leaves no 

 doubt thereof. The edge is very finely serrate in the outer part of the blade, smooth in the lower 

 part, as is also the edge of the basal part. The form of the basal part is not always as shown in 

 the figure 40, PL XVII, it is equally often without the narrowing towards the articular surface. The 

 neck is well developed, and is sometimes found somewhat retracted over the upper end of the stalk, 

 in a manner recalling the globiferous pedicellariæ of Strougyloccntrofus (comp. Part I. p. 163 PI. XX. 

 Figs. 25, 29). There may be a small ring at the lower end of the stalk. They are rather small, scar- 

 cely more than ca. o-2— 0-3'"'" length of head. — It is probably this form which Koehler mentions 

 and figures under the name of pédic. gemmiforme> (Sur les Echinocard. de la Méditerr. p. 184. PI. 4. 

 12), though I havæ not found any pedicellariæ resembling that figure very closely; j^robably it is not 

 really of Ech. fiavesccns. 



The tridentate pedicellariæ (PI. XVII. Figs. 11, 27, 31, 41) have broad, leafshaped valves, differing 

 somewhat in outline, as seen in the figures; in the small specimens the valves join in their whole 

 length, in larger ones the lower part is more or less narrowed, the edges being aj^art in about the 

 lower half of their length. The edge of the narrowed part is rather coarsely serrate, often with the 

 teeth placed in rather distant transverse series of 2 — 3 teeth in each; the edge of the outer part, 

 where the valves join is closely and finely serrate in the usual wa\'. There may be some meshwork 

 at the bottom of the blade in the larger specimens. Sometimes four-valved specimens occur. The apo- 

 physis may be finely serrate at its upper end. The neck is well developed; the stalk may have a 

 rather distinct ring below for the fastening of the muscles. They reach a considerable size, up to ca. 

 j.^min length of head. — It is to be remarked that the stalk of the tridentate, rostrate and triphyllous 

 pedicellariæ in the species of Echinocardmni consists of slender rods, which are almost not at all con- 

 nected by transverse rods, except above and below ; they differ herein from most other Spatangoids. 

 — The large tridentate pedicellaria figured by Koehler (Echinocard. de la Méditerr. PI. 4. 13) differs 

 considerably from those figured here; in faet, I have never seen any tridentate pedicellaria resembling 

 that figure in any of the numerous specimens of Echinocard. flavescens which I have exaniined. On 

 the other hånd I have found a quite similar form in a specimen received from Professor Koehler 

 under the name of Echinocard. pen>latifid^^vl from Tamaris s. Mer (Var). There seems to be some mis- 

 take here. (Comp. below, p. 142 — 4). 



The ophicephalous pedicellariæ (PL XVII. Figs. 7, 8) I have found only in young specimens (up 

 to a size of 18"""); they occur only on the actiual side in the naked posterior (bivial) ambulacra, and 

 may be very numerous. As is usual in Spatangoids they have no neck, the head resting directly on 

 the upper end of the stalk which is cupshaped widened; the stalk otherwise is composed of a rather 

 close, irregular meshwork. The valves are elongate, slender, widened towards the point, the basal part 



1 Koehler iRech. sur les Ech. des Cotes de Provence, p. 1301 however, states that no «substance muqueusej is 

 found here. 



