View this artwork by appointment, at Tate Britain's Prints and Drawings Rooms
Cecilia Powell has identified the subject of these two studies as the Sleeping Hermaphrodite, a classical sculpture which Turner saw in the Uffizi Gallery in Florence.1 The artist has made two variant views of the back of the statue, a Roman copy of an original Greek bronze. Further sketches of antique sculpture can be seen on folios 34 verso and 91 (D16549 and D16639), whilst a copy of a painting by Claude, also in the Uffizi, can be found on folio 60 (D16585). Turner also made an extensive study of statuary in the Capitoline Museums in Rome, see the Vatican Fragments sketchbook (Tate; Turner Bequest CLXXX).
Powell 1984, p.431 and Powell 1987, p.51.