Sea Urchins, Indian Marine Species - Informative & researched article on Sea Urchins, Indian Marine Species
 Indianetzone: Largest Free Encyclopedia of India with thousand of articlesHistory of India


in  
 Art & Culture|Entertainment|Health|Reference|Sports|Society|Travel
Forum  | Free E-magazine  | RSS Feeds  
History of India|Indian Temples|Indian Museums|Indian Literature|Geography of India|Flora & Fauna|Indian Purans|Indian Philosophy|Indian Administration|Indian Languages|Education
Home > Reference > Geography of India > Indian Natural History > Sea Urchins
Sea Urchins, Indian Marine Species
Sea Urchins are of three types which include true Sea-urchins, Cake-urchins and Heart-urchins. These are mostly found in low tide areas clinging to rocks.
 
 Sea Urchins, Indian Marine SpeciesSea Urchins are perhaps the most capricious fantastic of all echinoderms. They look like prickly balls or small rolled-up hedgehogs. Their size varies from four to twenty five centimetres. They are widely distributed in all shallow and coastal waters in the cracks and crevices of rock pools or amidst soft seaweeds. The deep-water forms are gregarious, covering large areas of the bottom. In appearance a sea urchin is very different from an armed starfish; yet it has the same fundamental structure. Especially it is a starfish and its globular form is the result of its five radial arms having bent upwards and united along their margins and tips.

Sea Urchins, Indian Marine Species In starfish the skeletal plates are only loosely connected by fibrous tissues but in a sea-urchin the plates are fused to form a hard shell enclosing all the soft parts of the animal including the tube-feet. The mouth however is uncovered. In life the plates are covered with slime outside and within and also between each plate. In a growing urchin these plates are continually thickened by a deposit of fresh limy matter formed by the action of slime and sea water. Additional plates are also added where the tips of the arms converge. Radiating upwards from the mouth along the arms are five bands of small holes through which the tube-feet can project. The pincers (pedicellarias) in a sea-urchin are most specialized than those of starfish in that they are stalked and have three jaws. The spines covering the entire body are brittle, long, sharp and movable. They aid the tube-feet in locomotion. It is a sight to see a sea-urchin moving on the tips of its spines, putting forth here and there its whiter elastic tube-feet. When some of the tube-feet shoot and touch the ground, those already in contact with the ground are pulled back. In a short time the protruded ones are withdrawn and the retracted ones projected and through this operation of the tube-feet coming out and going in the animal progresses. The enemies of sea-urchins are large fishes.

There are three types of sea-urchins - the true Sea-urchins which are globular, Cake-urchins with almost circular and flattened bodies, and Heart-urchins shaped like a heart. Sea-urchins are coloured differently in purple, green, ochre and blue. Under each type there are several interesting forms along Indian coasts.

Temnopleura toreumaticus is commonly found on Chennai beach. It is slightly conical in shape about four centimetres in diameter. The shell is greyish brown covered with somewhat long and reddish spines banded white. Stomopneustes variolaris is a big urchin with very long and thick spines mounted on tubercles and coloured purple. They are found at extreme low tide clinging to rocks. Among Cake-urchins several species of the genus Echinodiscus are common. They are recognised by the pair of oblique slits continuous with or near to the hind margin of the shell. One of the commonest Indian Heart-urchins is Echinolampas, having a slanting appearance and prominent petal markings.

(Last Updated on : 23/08/2014)
More Articles in Indian Natural History  (66)
 
Snails  (3)
 
Spider  (1)
 
Sponges  (1)
 
 
Algae  
 
Amoeba  
 
 
Clams  
 
 
 
 
 
 
 
 
Slugs  
 
 
 
 
 
Squids  
 
 
Recently Updated Articles in History of India
Educational Institutions in Ancient South India
Did you know that Education prevails in India right from the Vedic time when people learned the Upanishads.
Socio-Religious Reform Movements in India
Socio Religious Reform Movements took place in Bengal, Maharashtra, Uttar Pradesh and Punjab in British India. This movement had a great impact in shaping the contemporary society.
Yavana Invasion
Yavana invasion was probably the reason for the downfall of the Imperial Mauryan Empire in 187 B.C.
Trade under Mauryan Empire
Trade under Mauryan Administration was the first of its kind in South Asia. Internal trade expanded in India significantly due to political unity and internal peace at that time.
Role of King in Mauryan Administration
Role of king in Mauryan Administration reveals that the king maintained the social order by restraining the wrong-doers and ensuring the peace in the kingdom.
E-mail this Article | Post a Comment
Forum
Forum on Geography of India
Free E-magazine
Subscribe to Free E-Magazine on Reference
 
 
Sea Urchins, Indian Marine Species - Informative & researched article on Sea Urchins, Indian Marine Species
Sitemap
Contact Us   |   RSS Feeds
Copyright © 2008 Jupiter Infomedia Ltd. All rights reserved including the right to reproduce the contents in whole or in part in any form or medium without the express written permission of
Jupiter Infomedia Ltd.