REPOET ON THE HOLOTHHRIOIDEA. 
175 
plates. The tables have the perforated disk smooth, undulating, or provided with spines 
in the margin, and their spire, composed of four rods and one transverse beam, termin- 
ates in twelve teeth. The plates, much more numerous than the tables, and crowded 
in heaps, are commonly rounded, flat and disk-like, with the margin slightly uneven, 
and perforated by more or less numerous minute holes ; among these other more or less 
irregularly rectangular plates with fewer but larger holes are to be found. The dorsal 
conical appendages are alone furnished wdth transverse supporting rods near the more or 
less incompletely developed terminal plates ; the rest of the dorsal appendages as well as 
the ventral pedicels seem to be devoid of any rods or plates, or only have a few irregular 
plates round the terminal plate which is always well developed. Colour in alcohol, 
dark greyish-brovm on the back and the sides, and light almost whitish-grey on the 
ventral surface; the ventral pedicels brownish. Length about 190 mm. 
Habitat. — Simon’s Bay ; depth, 10 to 20 fathoms ; a single specimen. 
This species is remarkable in possessing, besides true minute dorsal pedicels, 
minute dorsal papillae which differ from the former not only in their exterior form, 
but especially in the presence of simple or slightly branched, strong rods. It seems 
as if the dorsal papillae are less numerous than the dorsal pedicels. 
The calcareous ring seems to be of the usual shape without posterior prolongations. 
The Polian vesicles are numerous, up to twelve or more, of unequal size, and some of 
them carry small branches at their base. A bundle of from five to sixteen madreporic 
canals wdth pear-shaped ends is situated on each side of the dorsal mesentery. The 
reproductive organs consist of a bundle of tubes, several times branched, situated on the 
left side of the dorsal mesentery. The respiratory-trees are well developed 
The tables (PI. YIII. fig. 7, a, b, c), when fully developed, have a simple circle of 
holes round the margin of the disk which attains a diameter of about 0'056 mm.; their 
spire is about 0’04 mm. high. Most of the disks are smooth, but I have often seen 
them with spines. In the pedicels, the disks of the tables are absent or reduced to a 
simple ring. The rounded flat plates, about 0‘03 mm. in diameter (PI. VIII. fig. 7, e), 
are characterised by their minute holes, and they seem to be collected into heaps in some 
parts of the body. The other plates (PI. VIII. fig. 7, d), which attain about the same 
size as the former, have a more irregular form, but they often present themselves under 
the shape of a more or less irregular rectangle ; they have some resemblance to cUsks of 
the tables, and their surfaces are not always quite even. The species in question is 
possibly identical with Ludwig’s Holothuria mexicana. 
Holothuria spinifera, n. sp. (PI. VIII. fig. 1). 
Body cylindrical, equally rounded anteriorly and posteriorly. The closed mouth 
surrounded by a collar of small papillre. Tentacles twenty (I). Anus vuth five groups 
