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THE VOYAGE OF H.M.S. CHALLENGER. 
be well developed. The longitudinal muscles each consist of two bands. The arms of 
the deposits of the body- wall (PI. X. fig. 13) are more or less strongly curved inwards, 
and have a length of up to 0'3 mm. ; their ends are slightly enlarged and spinous. The 
central, outwardly directed column has a length of about 0'24 mm. Both this column 
and the arms are remarkable in that the minute spines are mostly arranged in transverse 
bands or rings ; thus I counted five such rings in the central column and five to six or 
more in the arms. Sometimes the spines seem to be more irregularly scattered. The 
pedicels are strengthened by the same kind of deposits, though they are smaller, and 
also by some small simple spicules ; no terminal plates seem to be present. 
(?) Pcelopatides appendiculata, n. sp. 
Station 235, June 4, 1875; lat. 34° 7' N., long. 138° 0' E.; depth, 565 fathoms; 
bottom temperature, 38°’l ; green mud ; three specimens. 
Considering that all the three specimens brought home from the above-mentioned 
Station are rather macerated and defective, and that the calcareous ring and the deposits 
of the perisome are totally destroyed, I think it best to give a description without any 
previous diagnosis. 
The largest and best preserved specimen measures in length about 200 mm. The 
body is elongated and cylindrical, equally rounded anteriorly and posteriorly. The mouth 
is almost terminal, though ventral in position. The anus is dorsal. Bound the sides 
of the body, as well as round its anterior and posterior ends, the body-wall seems to be 
slightly thicker, but, as far as I can find, no true brim is discernible. Numerous closely 
placed conical and flexible processes run out from this thicker part of the body, and they 
are so arranged as to form a simple row round the body. The largest of these pro- 
cesses are about 10 or 15 mm. long. The dorsal surface also carries processes, but 
from the defective state of the specimens it is impossible to distinguish their size and 
distribution. However, they seem to be few in number, arranged only on the ambulacra 
in a simple row on each, and a pair of them, situated slightly in front of the middle 
of the body, is larger than the rest. A double row of pedicels is situated along the 
odd ventral ambulacrum, which appears to be naked only anteriorly. Thus all the 
interambulacra seem to be in want of ambulacral appendages. The tentacles are twenty, 
and consist of a small disk with about six digits or processes. The body-wall is very 
soft, spongy, thick, and swollen, probably from the influence of some acid in the alcohol. 
The colour in alcohol is sea-green, excepting along the middle of the ventral surface, 
where it is darkish brown, but probably the original colour is spoiled. 
A single Polian vesicle is present, 35 to 40 mm. long. The reproductive organs 
consist of a bundle of tubes on each side of the dorsal mesentery, each genital tube being 
branched three to five times. The most anteriorly situated tubes, which constitute each 
