This chapel, also known as Cappella Lancellotti, was erected by Carlo Fontana in 1670, on the commissioned by Card. Marzio Ginetti. The chapel is rich in colored marbles, among which are eight columns of verdi antique, four on the altar, and four at the sides of the two lateral monuments. The altarpiece, in the sculptural relief in white marble, depicting Angel Urges Sacred Family to Flee to Egypt (1675) is the work of Antonio Raggi. He sculpted the angel in the style of Bernini, his teacher.

(Another photo of altarpiece on the web here)