. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 176 ECHINOIDEA. I. — Tetradactylous pedicellariae I have not found. The tridentate and triphyllous pedicellariae as in fenestratum\ the large form of tridentate pedicellariae is found in very different sizes, but also the small ones are of the typical structure, so that they cannot be confounded with the other form. Besides the forms of the second kind of tridentate pedicellariae mentioned and figured for fenestratum, a form is also found here where the blade is not at all involved below (Fig. 10). I have, however, once foun
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. 176 ECHINOIDEA. I. — Tetradactylous pedicellariae I have not found. The tridentate and triphyllous pedicellariae as in fenestratum\ the large form of tridentate pedicellariae is found in very different sizes, but also the small ones are of the typical structure, so that they cannot be confounded with the other form. Besides the forms of the second kind of tridentate pedicellariae mentioned and figured for fenestratum, a form is also found here where the blade is not at all involved below (Fig. 10). I have, however, once found this form in A. fenestratum (in a specimen from Barbados, in British Museum), and so it can be no specific character. The spicules, perhaps, are a little smaller than in fenestratum, but this difference is too little marked to be used as a specific character. The best character is the colour, which in the preserved specimens is deeply dark violet, while all the specimens of fenestratum I have seen, are quite bleached in alcohol: also in the living animals the colour is quite different — comp. the description by Wvv. Thomson. The primary spines on the actiual side are dark with a rather large, white hoof, very conspicuous on the dark ground-colour. — The organs of Stewart are very large; the longitudinal muscles powerful. -- For this species, the place of which is evidently between A. fenestratum and coriaceum, I propose the name of Araeosoma violaceum n. sp. Echinosoma uranus (p. 57). A couple of speci- mens of this species ( Talisman Sahara, 938 m.) I have seen in the museum of Paris. All the primary spines on the actiual side were broken, but some of the spines round the mouth had a little hoof; after this there can be no doubt that the primarv spines 011 the actiual side end in a hoof as in E. teiiue. The large tridentate pedicel- lariae are quite similar to the one of E tenue figured on PI. XII. Fig. 35, with the exception that here the apophysis does not continue i
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