Leaning with braceleted right hand holding a staff, residing on the mount of the Bull, with Graceful eyes, the blessing hands holding axe and deer, with an eye in forehead, blissful, three eyed, the hair wound as crown, with gauri to his left, Doing good to one who worships, to that God,R^ishabhArUDha (salutations).
R^ishabha ArUDhar : deity sitting on the Bull(bhOga mUrti)
This is one of the very auspicious mUrtis, praised in periya purANam as blessing the devotees for their great deeds.
There are two bull vehicles associated with Lord shiva. They are the mahAviShNu bull and the bull of justice.
dharma dEvatA(divine of justice), in order to be immortal, worshipped God very ardently. God as an indication of the justness ever, took the dharma as the bull vehicle. Thus dharma attained endlessness.
During tripura samhAra(1) as soon as the God put Its leg on the chariot, which the divines proudly thought "they" made it for God, the chariot's axle broke off ! The divines realized the futility of their pride. In the meanwhile Lord viShNu took the form of a bull, on which Lord shiva sat. This is the viShNu bull vehicle of God.
Check here for a mUrti in many ways like RishbhArUdar. (Additionally skandha is also seen.)
1. tripura samhAri