CHAP. ix.J THE DEEP-SEA FAUNA. 459 



tus, Psammechinus niiliaris, Echinocyamus angulatus, 

 Amphidetus cordatus, and Spatangus purpureus — may 

 be regarded as denizens of moderate depths intlie 

 ' Celtic province,' recent observations having merely 

 shown that they have a somewhat greater range in 

 depth than was previously supposed. Probably Spa- 

 tangus raschi may be an essentially deep-water form 

 having its head-quarters in the same region. Seven 

 species — Cidaris papillata, Echinus elegans, E. nor- 

 vegicus, E. rarispina, E. microstoma, JBrissopsis lyri- 

 fera, and Tripylus fi-agilis — are members of a fauna 

 of intermediate depth ; and all, with the doubtful ex- 

 ample of Echinus microstoma, have been observed in 

 comparatively shallow water off the coasts of Scan- 

 dinavia. Eive species — Cidaris affinis. Echinus melo, 

 Toxopneustes brevispinosus, Psammechinus micro- 

 tuberculatus, and Schizaster canaliferus— are recog- 

 nized members of the Lusitanian and Mediterranean 

 faunse ; and seven — Porocidaris purpurata, Phor- 

 mosoma placenta, Calveria hystrix, C. fonestrata, 

 Neolampas rostellatus, Pourtalesia jeffreysi, and P. 

 phiale — are forms which have been for the first time 

 brought to light during the late deep-sea dredging 

 operations, whether on this or on the oi^er 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 — Cal- 

 veria, 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 



