306 Miscellaneous. 2. S. Itaschi, Loven. This species is apparently gregarious, and is enormously abundant in patches here and there from the Fseroes to the Strait of Gibraltar at depths of from 100 to 300 fathoms. Of the twenty-seven species observed, six (namely Echinus Flem-ingii, Sphcerechmus esculentus, Psanimechinus miliaris, Echinocya-mus angulatus, Amphidetus ovatus, and Spatanyus purpiireus) may be regarded as denizens of moderate depths in the " Celtic province," recent observations having merely shown that they have a somewhat greater range in depth than was previously supposed. Probably Spatanyus Raschi may simply be an essentially deep-water form having its headquarters in the same region. Eight species (Cidaris pupillata, Echinus eleyans, E. norveyicus, E. rarispina, E. micro-stoma, Toxopneustes drobachiensis, Brissopsis lyrifera, and Trij}ylus /rayilis) are members of a fauna of intermediate depth ; and all, with the doubtful exception of Echinus microstoma, have been observed in comparatively shallow water off the coasts of Scandinavia. Five species {Cidai-is affinis, Echinus melo, Toxopneustes brevispinosus, Psummechinus microtuberculatus, and Schizaster canaliferus^ are recognized members of the Lusitanian and Mediterranean faunae, and seven (Porocidaris purjmrata, Phorjnosoma placenta, Calveria hystrix, C. fenestrata, Neolampas rostellatiis, Pourtalesia Jeffreysi, and P. j)hyale) are forms which have for the first time been brought to light during the late deep-sea dredging-operatious, whether on this or on the other side of the Atlantic: there seems little doubt that these must be referred to the abyssal fauna, upon whose confines we are now only beginning to encroach. Three of the most remarkable generic forms, Calveria, Neolampas, and Pourtalesia, have been found by Alexander Agassiz among the results of the deep-dredging operations of Count Pourtales in the Strait of Florida, showing a wide lateral distribution ; while even a deeper interest attaches to the fact that while one family type, the Echinothuridse, has been hitherto known only in a fossil state, the entire group find nearer allies in the extinct faunas of the Chalk or of the earlier Tertiaries than in that of the present period. MISCELLANEOUS. On Thread-cells and Semen in Marine Sponges. By T. Eimer. The researches ■which have been made during the last few years on sponges have led to the recognition of striking affinities between these animals and the Ccelenterata ; nevertheless certain important differences in their organization and, in particular, in their histolo-gical structure even recently checked those who would have been most disposed to unite these two groups. M. Hiickel said, in 1869 : — ^'The comp)lete absence of the urticant organs in all the Sponges, the constant presence of these same organs in all the Coralliaria, the Hydromedusae, and the Ctenophora, constitute at present the sole 'morp>hological character which separates in a clear and definite manner the first of these classes from the three others. I have in con-
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