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- 



