CHAP. IX. | THE DEEP-SEA FAUNA. 459 
tus, Psammechinus miliaris, Echinocyamus angulatus, 
Amphidetus cordatus, and Spatangus purpureus —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 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, H. rarispina, EL. microstoma, Brissopsis lyri- 
fera, and Tripylus fragilis—are members of a fauna 
of intermediate depth ; and all, with the doubtful ex- 
ample of Zchinus microstoma, have been observed in 
comparatively shallow water off the coasts of Scan- 
dinavia. Five species—Cidaris affinis, Echinus melo, 
Toxopneustes brevispinosus, Psammechinus micro- 
tuberculatus, and Schizaster canaliferus—are recog- 
nized members of the Lusitanian and Mediterranean 
faunee; and seven—Porocidaris purpurata, Phor- 
mosoma placenta, Calveria hystrix, C. fenestrata, 
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 other side of 
the Atlantic. There seems littlé 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 
