ECHINOIDEA. I. 



consists of long, thin calcareous threads connected by small cross-beams. -- Perrier 1 ) states that the 

 valves of the globiferous pedicellarias end in two hooks situes snr le meme plan . This is absolutely 

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

 tridentate pedicellarise (PI. XVII. Figs. 2, n, 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 Echinus-species. The bottom of the blade is filled by a rather well developed net of meshes. 

 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 pedicellarise are also found 

 on the buccal plates; 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 pedicellariae is decoupe en un nombre assez grand de dents pointues ; as stated above 

 I have only found 2 4 teeth. The ophicephalous pedicellarise show no marked peculiarities; the blade 

 is rather narrow, with well developed mesh-work (PI. XVII. Figs. 8, 28). The triphylloiis pedicellariae 

 (PI. XVII. Figs. 14, 25) are distinguished by the very finely rounded form of the blade. -- The sphse- 

 ridiae (PI. XVII. Figs. 26, 27) are quite smooth. 



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



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



figured by Perrier as belonging to this species, no doubt belong to Strongylocentrotits drobachiensis. 



There are no bihamate spicules in the gills or the buccal membrane, nor in the pedicellarice 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 coasts of Norway it is common, at all events to Troudhjem; further it is found at 

 Iceland and the Faroe Islands, but not at Greenland or North America. To the south 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 may be found on still greater depths. At the Faroe Islands I have taken a large 

 specimen on a depth of 100 fathoms; this fact, however, is a little uncertain. The locality is a little 

 range of the sound between Nols0 and 0stnses; 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, stony bottom. 



Subfam. Echininse. 



j 



12. Echinus elegans Dub. Kor. 



PI. I. Figs. 23. PI. III. Fig. 4. PL XV. Fig. 4. PI. XVI. Figs. 3, 19. PI. XVIII. Figs. 2, 3, 22, 26. PL XIX. Figs. 10, 26. 



PL XX. Figs. 8, 9, 19, 22, 23. 



Synonym: Echinus Wallisi Ag. (?) 



Principal literature: Diiben & Koren: Ofvers. af Skandinaviens Echinodermer. p. 272. - 



T ) Recherches sur les Pedicellaires. p. 146. PL V. 



