PORCUPINE’ DEEP-SEA DREDGING-EXPEDITIONS. 
725 
Pig. 1. 
region, they become entirely obsolete and the spine is perfectly smooth. The radioles 
of the second size are about 8 millims. in length and 2 millims. in width, very much 
compressed and flattened, rounded at the end and finely striated longitudinally. They 
are articulated in a single row to the small tubercles round the edge of the areola, and 
in their natural attitude they lean over the naked part of the areola and cover the 
muscles and the head of the large radiole like a frill. A series of very much smaller 
spines are attached to the rows of larger granules which border 
the raised ambulacral band, and these are laid over to either 
side, covering and protecting the pore-arese. These small 
pointed spines have a deep depression running down the centre, 
almost giving the idea of a tendency to divide into two. The 
miliary granules over all parts of the shell bear small flat- 
pointed spines. Only very minute granules bear pedicellarise, 
which are of three forms. The most conspicuous of these are 
remarkably large, about 1*5 millim. in length and nearly a mil- 
limetre in width. The valves are greatly inflated, the central 
chamber large, and the ridges prominent (woodcut, fig. 1). 
These pedicellarise are abundant and developed to a large size 
on the apical disk, particularly in northern examples (Plate 
LIX. fig. 5). Pedicellariae of another form, with the valves 
long and slender, are ranged among the secondary spines along 
the borders of the ambulacral are® and round the bases of the 
primary radioles (Plate LIX. fig. 6) ; and smaller tridactyle 
pedicellariae, closely resembling a form very common in the 
Echinidae, are scattered apparently irregularly all over the test. 
Cidaris papillata has a very wide distribution. We dredged 
it in from 100 to 400 fathoms wherever there was a gravelly or 
sandy or in any way a hard bottom, in one continuous belt from 
the Faeroe Islands to Gibraltar. Though not so abundant, it Valve of a P edlcellaria from 
was frequent to 600 and 800 fathoms; and on one or two tlle apical disk of Cidcms 
. . papulatu. x 80. 
occasions small specimens were brought up from upwards of 
1000 fathoms. In some localities the number of individuals was quite surprising. In 
the Shetland sea and at some stations off the south and west of Ireland, the dredge-bag 
was almost choked with them. Cidaris papillata is common off the coast of Norway. 
Specimens from Norway and the north of Scotland have the test usually thick and 
strong, the spines stout and comparatively smooth, and the large inflated pedicellarise 
very numerous on the apical disk. Specimens from the Mediterranean, where the 
species is abundant, passing in some places into much more shallow water, are named 
in our Museums Cidaris hystrix, and are usually regarded as having the spines longer, 
more slender, and more markedly echinated, and the pedicellarise less numerous than 
in the northern form. After examining a very large number of specimens from all 
