148 THE ATLANTIC. (CHAP. I. 
which are imbricated like the slates on the roof of a house, the 
shell being perfectly flexible. One marked character, however, 
of the northern species was that the lower (oral) surface of the 
test was quite different in character from the apical surface, the 
pore areze and the water-feet on the lower surface being re- 
duced to insignificance, and the test uniformly studded with 
tubercles for primary spines surrounded by enormous areole, 
giving attachment to masses of muscle quite out of proportion 
to the size of the spines. In the only specimen which we pro- 
cured, the spines on the oral surface were broken and incom- 
plete, but I remarked on this curious disproportion when brief- 
ly noticing the species.* After going over the siftings from 
the Porcupine dredgings, Dr. Carpenter sent me, with a num- 
ber of other things tncerte sedis, one or two peculiar conical 
calcareous bodies jointed on short stalks. These I recognized 
as a part of some unknown echinoderm, what part I was at a 
loss to conceive. Curiously enough, a couple of days ago (June 
13th, 1874) we dredged in 400 fathoms 100 miles to the east- 
ward of Sydney, a splendid specimen, a foot in diameter, of an- 
other species of Phormosoma (Fig. 35), all the primary spines 
Fia. 35.—Phormosoma hoplacantha, Wyvi.tE Toomson. Southern Sea, between Australia 
and New Zealand. Portion of the ventral surface of the test. Reduced one-third. 
of the oral surface tipped with calcareous cones, identical in 
structure with those found on the Scottish coast, but consider- 
* “The Depths of the Sea,” page 161. London, Macmillan & Co., 1873. 
