142 ECHINOIDEA. I. 



consists of long, tliin calcareoiis threads connected by small cross-beams. — Perrier") states that tlie 

 valves of the globiferous pedicellariæ end in two hooks situés sur le méme plan . This is absohitely 

 wrong; I suppose he must have interpreted the edges of the poison canal as two separate teeth. The 

 tridentate pedicellariæ (PI. XVII. Fig.s. 2, 11, 22) with rather broad, not very deep blade; the outer 

 part, where the valves join, is somewhat widened and sinuate in the edge. The whole edge is serrate, 

 coarsely below, finely above, but there is only a single series of teeth, they form no transverse series 

 as in the Ef/ti//i/s-species. The bottoni of the blade is filled by a rather well developed net of raeshes. 

 The apophysis has 2 — 4 rather large indentations at the upper end. The valves are rather wide apart 

 through the greater part of their length. In larger specimens tridentate pedicellariæ are also found 

 on the buccal piates; they are smaller than the others, more spoon-shaped ; the edge more straight, 

 and there is no mesh-work at the bottom (Fig. 2). According to Perrier (loc. cit.) the apophysis of 

 the tridentate pedicellariæ is découpé en un nombre assez grand de dents pointues ; as stated abo\e 

 I ha\-e only found 2 — 4 teeth. The ophicephalous pedicellariæ show no marked peculiarities; the blade 

 is rather narrow, with well developed mesh-work (PI. XVII. Pigs. 8, 28). The triphyllous pedicellariæ 

 (PI. XVII. Pigs. 14, 25) are distinguished by the very fineh' rounded form of the blade. — The sphæ- 

 ridiæ (PL XVII. Pigs. 26, 27) are quite smootli. 



The spicules in the tube feet are very few, often quite wanting. They are bihamate, ver\- 

 small (PI. XVII. Pig. 10); just below the sucking disk they may be a little irregular. The spicules 

 figured b}- Perrier as belonging to this species, no doubt belong to Strougyloccntrotus drobacliiensis. 

 — There are no bihamate spicules in the gills or the buccal membrane, nor in the pedicellariæ or in 

 the .skin at the base of the spines. 



It is a small species; a specimen of a diameter of 35'"'" is uncommonly large. It is very 

 common in the Danish seas, quite down in the western part of the Baltic but not in the eastern 

 part. Along the coa.sts of Norway it is common, at all events to Trondhjem; further it is found at 

 Iceland and the Paroe Islands, but not at Greenland or North America. To the soutli it is found at 

 the coasts of Great Britain and along the Atlantic coasts of Europe quite down to Morocco. Bell 

 (Catalogue. p. 151) states that it is also found in the Mediterranean. 



It is a pronounced littoral form, often found just at the beach; but it is common down to 

 ca. 50 fathoms, and ma}' be found on still greater depths. At the Paroe Islands I have taken a large 

 specimen on a depth of 100 fathoms; this faet, however, is a little uncertain. The localit>- is a little 

 range of the sound between Nolsø and Østnæs; it is not impossible that the dredge has got in on 

 more shallow water at the edge of this deep hole, so that the animal may have been obtained there. 

 It prefers hard, stou)- bottom. 



Subfam. Echininæ. 

 12. Echinus elegans Diib. Kor. 



PI. I. Figs. 2— 3. PI. III. iMK. 4. PI. XV. Fig. 4. PI. XVI. Figs. 3, 19. PI. XVIII. Figs. 2, 3, 22, 26. PI. XIX. Figs. 10, 26. 



PI. XX. Figs. S, 9, 19, 22, 23. 



Synonym: Echinus W'allisi Ag. (?) 



Principal literature: Diib en & Kor en: Ofver.s. af vSkandinaviens Echinodermer. p. 272. — 



') Recherches sur les Pédicellaires. p. 146. PI. V. 



