Habit and habitat: Cucumaria is inhabits about 200 fathoms deep wholly or partially buried in the mud. It feeds on detritus and plankton.
Distribution: It has cosmopolitan distribution and specially found in Europe, U.S.A. and India.
- Commonly called as sea cucumber.
- Body is elongated horizontally along the oral aboral axis. Color of the body may be whitish, reddish or brown.
- Oral end contains a whorl of 10 dendritic bushy, pinnately- branched tentacles surrounding the terminal mouth. Tentacles are modified tube feet.
- Mouth anterior in position.
- Rest of the body differentiated into 5 ambulacral grooves are covered and run longitudinally.
- Tube feet, when present, usually possess suckers and are either arranged in rows or are irregularly scattered.
- Body wall which is dermo-muscular contains very small separate ossicles.
- There is a single genital aperture, middorsally situated between the bases of two adjacent inter-ambulacral tentacles near mouth.
- Animal rests on the so-called ventral surface, which flattened and paralleled with oral-about axis of the body, and is pentaradiate. It has 3 ambulacral areas trivium and forms sole. Dorsal surface with 2 ambulacral areas is called as bivium.
- Anus is aboral with paired respiratory trees. The haemocytes in the coelomic fluid also contain haemoglobin. Lacunar network is absent.
- Larva is characteristically an auricularia which develops into a doliolaria before metamorphosis.
Identification: since the specimen contains whorl of pinnately branched tentacles, hence it is Cucumaria.