Home > Indian History > History of India > Ark Shells
Ark Shells
Ark Shells belong to the family of mollusks. There are around two hundred species of ark shells that are found within its family.

Share this Article:

Ark ShellsArk Shells are widely distributed along the Indian shores. The shells are readily recognised by their long and straight upper margin which bears numerous, tiny plate-shaped teeth. This particular arrangement is present in arks alone and not found in any other group of bivalves. An ark-shell with closed valves looks like a small box and that may be the reason as to why it is called Arca, which in Latin means a box.

Arks are more primitive than oysters and clams. Their foot is normal and bears a byssus. Their breathing organs are simple gills formed of thread-like filaments arranged parallel to one another. The lower parts of their filaments are folded upwards and connected by hair-like cilia. The mantle consists of two lobes covering the gills as in other bivalves but their lower edges are free, i.e. they are not united at any point to form a siphon as in higher bivalves like clams. The animal keeps the mantle margins gaping to allow fresh water to enter into and the used water to escape from the mantle cavity. This kind of simple gills and open mantles are found in mussels and scallops also.

Ark Shells There are many species of arks varying widely in appearance, size and habits. Their shells are invariably ribbed, generally white, grey or brown in colour. In life most of them are covered by a greenish or dirty black bristly protective coating called the periostracum. Their habits vary. Many members live buried where mud is mixed with sand. Some attach themselves to mud-covered rocks and coral reefs, some to masses of pebbles and clusters of broken shells, and some find their way into crevices of stones and hardened mud. Their habitat or the nature of surface on which these animals settle and grow-affects the symmetry and appearance of the shells. Arks are not gregarious and do not form regular beds as oysters or mussels do.

Some of the popular species within the family of the Ark Shells are:
1. Area granosa is a handsome, heart-shaped ark which is 4 to 5 cms long. Its valves are thick and white with knobs along their ribs. Their blood and flesh are reddish in colour instead of light bluish as in other molluscs: hence they are called Blood Arks. The flesh is said to be tough and highly nutritious. This species is found in plenty in knee-deep mud by seashores, in backwaters and estuaries. Some of them ascend rivers far interior.

2. Arca symmetrica are the smallest of all common arks and is scarcely one cm long. Shell valves are symmetrical, dainty, finely ribbed and pure white in colour. Arks arc not generally gregarious but this species conga-gale are found under stones in the littoral region or attach themselves in assemblages to blocks of dead coral reefs.

3. Arca fusca, popularly known as the Banded Ark, is marked by deep chestnut colour, three whitish bands radiating from the centre of the upper margin and finely sculptured ribs. In life the shell is mostly covered by a black hairy coating. This species lives 4 to 5 fathoms deep, lying half buried in the muddy sand bottom.

4. Area tortuosa is the most curious ark. Its shell has more length than breadth and has a twisted appearance: the front portion is twisted to the left and the hind portion to the right. It is believed that the abnormal distortion is because the animal tries hard to fit itself into habitats like rock cervices and mud banks.


Share this Article:

Subscribe to Newsletter
Learn unknown facts about India from a curated list of informative articles.

Related Articles

More Articles in History of India

History of Indian Drama
History of Indian Drama is rich with Vedas and Indian epics and has gradually changed with time and remains unaffected by any foreign influence.
History of Khajuraho Temple
Located in the Chhatarpur district of Madhya Pradesh, Khajuraho is country’s most magnificent groups of temples.
History of Ayurveda
History of Ayurveda dates back to 5,000 years old and is widely considered to be the oldest form of health care in the world.
History of Uttar Pradesh
The state was the heart of Mahabharata war and the history of Uttar Pradesh is very much the history of India. The place finds its mentions in Hindu epics Ramayana and Mahabharata.
History of Indian Photography
An overview of the development of photography, through the various stages in India.
History of Delhi
History of Delhi began with the advent of Indian regal dynasties. Delhi witnessed the rise and fall of Hindu dynasties, Muslims and the British as well.
History of Indian Radio
History of Indian Radio dates back to late 1930s with the first establishment of All India Radio in 1936 that improved further after independence.
History of Punjab
History of Punjab dates back to the 16th century; however its formation is traced in the great epic Mahabharata.
History Of Archaeology In India
History of archaeology in India contributes a lot to define the past history and the social life of India.
History of Maharashtra
Maharashtra, the land of charismatic Marathas, unfolds the legend of diverse culture and tradition, keeping in pace with the modernity. The gallant history of Maharashtra is still echoed amidst its historical relics and archeological wonders.
History of Kerala
History of Kerala can be interpreted from the inscriptions of Ashoka, Mauryan Emperor. History of Kerala is as interesting as its wide-ranging geographical features that make the land a place of versatile appeal.
History of Bihar
History of Bihar goes back to the very dawn of the human civilizations. Many eminent personalities and leaders from Bihar contributed for India’s freedom struggle.
History of Assam
In the ancient Indian epics like Ramayana and Mahabharata, Assam was known as `Kamarupa` or `Pragjyotish`. In the Mahabharata, the Puranas, the Tantras there are references of Assam as Kamrupa kingdom.
History of Andaman and Nicobar Islands
History of Andaman and Nicobar Islands dates back to the settlement of the East India Company in the territory of the Islands.
History of West Bengal
History of West Bengal is rooted in richness and is an important episode in the history of India. The history of Bengal played an important role in shaping the history of India.
History of Jharkhand
One of the fairly newer states, Jharkhand was carved out of the southern portion of Bihar in 2000. The history of Jharkhand is seeped with a variety of cultural significances starting from the Vedic era to Mughal period and finally the British administration.
History of Sikkim
History of Sikkim declares the pre historic culture and the colonial era hilly politics and the rules of Sikkim.
History of Nagaland
The history of Nagaland mainly revolves around and deals with the customs and economic activities of the Naga Tribes and how the state has evolved since the Indian Independence.
History of Mizoram
History of Mizoram includes the various historical events and incidents which occurred during the various ages, right from before the age of the Mughals.
History of Jammu & Kashmir
History of Jammu and Kashmir involves a series of political and geographical transformations from every ancient era to the modern times also. Even now, Jammu and Kashmir has its political tension between Pakistan and India.
History of Puducherry
Puducherry was invaded by different invaders in different times. The invaders include Pallava Kingdom of Kanchipuram, dynasties of the South, Cholas of Thanjavur, Pandyas and Muslim invaders.
History of Chandigarh
In 1947, the British India was partitioned into India and Pakistan. Punjab was also included in this partition. So, there was a need for a new capital for Punjab, as the old capital Lahore became part of Pakistan during the partition. So, in 1948, under the leadership of chief architect Mr. P.L. Verma the construction of Chandigarh city began.
History of Daman and Diu
During the early stage, i.e. from 8th to 13th century, Daman and Diu was part of Goa.
History of Lakshadweep
History of Lakshadweep defines the first settlement on these islands under the Union Territory of India that was ruled by Cheraman Perumal, who was the last king of Kerala.
History of Karnataka
History of Karnataka comprised of the different rulers of different dynasties of various religions like Hindus, Buddhists, and later the Muslims.
History of Goa
History of Goa dates back to the 3rd century BC and reflects the rule of the mighty rulers and gained its independence under Jawaharlal Nehru.
History of Arunachal Pradesh
Arunachal Pradesh possesses a rich historical heritage of culture of the ancient tribes. Being a bordering state of India, Arunachal Pradesh also has a history of military unrest since ancient Indian age.
History of Andhra Pradesh
History of Andhra Pradesh traces its origin back to the 5th century BC. According to the inscriptions, Kuberaka, the oldest Kingdom in South India had an empire in the coastal Andhra during that period.
History of Himachal Pradesh
History of Himachal Pradesh narrates about the various settlements and dynasties that emerged in the region over time.
History of Uttarakhand
History of Uttarakhand finds mention in the early Hindu scriptures as Kedarkhand, Manaskhand and Himavat. Uttarakhand is called as the Land of the Gods (Dev Bhoomi) because of its various holy places and shrines.
History of Rajasthan
The history of Rajasthan is dotted with tales of valor, chivalry, camaraderie and romance.
History of Tamil Nadu
History of Tamil Nadu reveals that this ancient place in South India was ruled by various kingdoms like the Pandyas Dynasty, Cholas Dynasty, Nayakas Dynasty and Pallavas Dynasty.
History of Haryana
History of Haryana depicts various events and influences that have cast a profound effect on the culture and people of the district. The place gained statehood on 1st of November 1966
History of Odisha
History of Odisha goes back a rather long way. Most of the history of the state is replete with the dynastic as well as tribal struggle for territorial superiority. Odisha is a place where one can find the religion, culture and history flow in away that lead to cultural amalgamation of early India.
History of Manipur
History of Manipur can be traced back to the prehistoric ages and this was followed by a number of rulers who reigned the land from age to age till it came under British rule and later joined the union of India.
History of Gujarat
History of Gujarat can be dated back to the 14th century that later witnessed the supremacy of many powerful dynasties.
History of Tripura
History of Tripura is dealing with the early mythological history and the history of British rule in North eastern part of India.
History of Meghalaya
The history of Meghalaya predominantly comprises of the three tribes of the state- Garo, Khasi and Jaintia tribes. Later on Meghalaya was formed by carving out two districts from the state of Assam.
History of Chhattisgarh
History of Chhattisgarh dates back to the era of epics and traces through the reign of powerful dynasties in India like Marathas. The area developed a rich cultural heritage during British era.