This is Mahishasuramardini (Killer of the demon Mahisha) shown with eighteen arms. She is known as Durga in Bengal and elsewhere in India, she is considered as a form of Durga. She is standing with her right leg on a Mahisha, in buffalo form, holding him by his hair and is about to plunge Trishul into his chest. (Trishul/Trident is missing). The severed head of buffalo is on her left front. Her vahana, a lion is one her right, is looking menacing with raised right paw. The bronze has an oval base.
The story is, Mahisha through austerities obtained invincibility in war and could not be defeated/contained by Gods. The Gods led by Brahma approached Siva and Vishnu. And thru them, the power, energy and anger of all Gods were combined to take the shape of Goddess.
According to Markandeya Purana ” Siva presented the trident to the goddess, Vishnu the discuss, Varuna the conch, Agni the spear, Vayu the bow and quiver, Indra the vajra and the bell that was tied to his elephant Vahana, Yama the cudgel, Varuna the noose, Prajapati the necklace, Brahma the water pot, Surya the dazzling brilliance, Kala (destiny) the sword and shield, Viswakarma the ornaments and weapons (axe, mace, armour), Himavan the lion for mount, Kubera the bowl for liquor and Ananta the serpent ornaments”.
The above paragraph is based on S K Ramachandra Rao’s Pratima Kosha Vol 5 page 74. Different Puranas differ in detail. But all talk about Durga getting powers from different gods and thus representing all the protective forces in the world.
The attributes in her hands are not readily discernible and the above reference contains a list of attributes she carries.
The forehead appears to have smoothed thru worship and it is possible the lower front portion of the crown was reworked.
I have seen two other almost identical bronzes. But the wear on them is much less. Quite likely they are from the same workshop. This bronze is about 20.5 cm in height. It is very heavy.
This may not be earlier than the 19th century and it is quite likely it was made for trade.
Added on 21 Aug 2016: One of more the experienced collectors (DB) pointed out that quite a few bronzes with these characteristics are in the marketplace for this to be an antique. I agree with him. Hence the classification ‘reproduction’.
10 Feb 2020: The book Die Anderen Gotter (The other Gods) edited by Cornelia Mallebrein, has an example of similar bronze. Item 178 and page 243. That example is from a household shrine and the text mentions that Vigraha has been with the family for 250 years. Hence the doubt about this being a reproduction. Will retain it.