Molpadida is an
order
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
...
of
sea cucumber
Sea cucumbers are echinoderms from the class (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...
s. The body shape is
fusiform
Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...
and unlike other sea cucumbers, their hind body is narrowed to form a distinct tail. Although they possess tentacles around the mouth derived from the
water vascular system
The water vascular system is a hydraulic system used by echinoderms, such as sea stars and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. Echinoderms mo ...
, they have no true
tube feet
Tube or tubes may refer to:
* Tube (2003 film), ''Tube'' (2003 film), a 2003 Korean film
* "Tubes" (Peter Dale), performer on the Soccer AM#Tubes, Soccer AM television show
* Tube (band), a Japanese rock band
* Tube & Berger, the alias of dance/e ...
, and are therefore believed to be related to the
Apodida
Apodida is an order (biology), order of littoral to deep-sea, largely Fauna#Infauna, infaunal Holothuroidea, holothurians, sea cucumbers. This order comprises three families, 32 genus, genera and about 270 known species, called apodids, "without ...
.
They have fifteen much branched tentacles and a stout body. They have tentacle ampullae and respiratory trees present, a kind of water lung attached to the cloaca. The
ossicles
The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. Although the term "ossicle" literally means "tiny bone" (from Latin ''ossi ...
, minute calcareous plates embedded in the skin and characteristic of each species, take the form of tables, anchors, fusiform rods and perforated plates but never wheels.
An illustrated key to the sea cucumbers of the South Atlantic Bight
Retrieved 2012-02-12.
Like their relatives, they are adapted for burrowing into soft sediment, but they are relatively sedentary, rarely moving once they have excavated their burrow. Their burrow is U-shaped, with the animal's tentacles projecting from one end.
Notes
References
*
Echinoderm orders
Taxa named by Ernst Haeckel
{{Holothuroidea-stub