[ 95 J 
very much shorter than the horizontal one from lip to lip of 
the arms, whilst in the regular species of Sea-Urchins it may 
approach the horizontal axis in length. The Holothurians are 
the only class of Echinoderms in which the proportions are 
reversed. Their body is greatly elongated in the direction of 
the principal axis and assumes the shape of a sausage. Their 
popular name of ' Sea-Cucumbers * is due to this shape. Com- 
mercially they are known as ' Trepang ' or * B£-che-de-mer.* 
Their skin is leathery, the calcareous plates of other Echino- 
derms being reduced to microscopic spicules. The tube-feet 
are generally present, but are not always regularly arranged. 
The body is in many cases somewhat bilaterally symmetrical, 
the animal having adopted the habit of creeping on a certain 
side of its body. The mouth is surrounded by a fringe of 
branched retractile feelers or tentacles. 
The Holothurians are divided into five orders of which 
three are represented in the collection, vi^ the Aspidocftirota, 
Dendrochirota and Synaptidd. 
The Aspidochirota have shield-like feelers. It is the 
most important of the five orders, not only because they form 
nearly one third of all Holothurians, but also because apparently 
all edible species belong to it. Many species of this order may 
be collected here at low tide, and when seen lying on the sand 
these black sausage shaped creatures, with their slimy and 
sticky skin, are certainly the least attractive of marine animals 
especiaHy as when handled, they shoot out the greater part of 
their intestine. However, when seen in clear water, with their 
feelers fully expanded, they offer a very much more pleasing 
and interesting appearance. The collection contains, besides 
seven species of ffahtfiuria, also a specimen of the so-called 
* Prickly-red ' fStkiwiJHs vitnegaius). It is yellowish-brown 
in colour, with red papillae, Saville Kent, in his ' Great Barrier 
Reef of Australia,' gives a graphic description of the Trepang 
fishery in Queensland, The animals when collected, are first 
boiled for twenty minutes in large iron caldrons, then split up, 
cleaned, roughly dried in the sun, then transferred to the smoke- 
house, placed on tiers of wire netting anci smoked for twenty- 
four hours by a wood fire. They then look like charred sau- 
sages. It is essential that they are absolutely dry when packed 
for shipment, the proof of their good condition being that 
"they rattle like walnuts in their bags/' They arc practically 
only for the Chinese market. 
The extent of the trade in this article in Singapore is 
seen from the following figures : during the year 1907, trepang 
