Hermes (and a herm to his side).

Roman sculpture following Hellenistic examples. 2nd century AD.
Hermes is holding a purse in the right hand, indicating his capacity as protector of trade.

Hermes (Greek: Ἑρμῆς) is an Olympian god in Greek religion and mythology, son of Zeus and the Pleiad Maia. He is second youngest of the Olympian gods. Hermes is a god of transitions and boundaries. He is quick and cunning, and moved freely between the worlds of the mortal and divine, as emissary and messenger of the gods, intercessor between mortals and the divine, and conductor of souls into the afterlife. He is protector and patron of travelers, herdsmen, thieves, orators and wit, literature and poets, athletics and sports, invention and trade. In the Roman adaptation of the Greek pantheon, Hermes is identified with the Roman god Mercury, who, though inherited from the Etruscans, developed many similar characteristics, such as being the patron of commerce.

A herm is a sculpture with a head, and perhaps a torso, above a plain, usually squared lower section, on which male genitals may also be carved at the appropriate height.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Arkeoloji ve Sanat’ Dergisi n° 38 & Wikipedia.