Near the end of Telemachus, on old man pops to the surface of the water and clambers up the rocks, water running off of his body and bathing trunks. Glancing at Stephen and Haines, Mulligan crosses himself, which is our cue to infer that the swimmer is a priest. The suspicion is confirmed later when the narrative mentions "The priest's grey nimbus in a niche where he dressed discreetly." The nimbus seems to refer to a "garland of grey hair" seen earlier on the old man, and the niche to a gap between rocks on the shore where he can modestly remove his swimsuit.

JH 2011

Mercury Appearing to Aeneas, a fresco painting by Giovanni Battista Tiepolo (1757), displayed in Villa Valmarana, Vicenza. Source: Wikimedia Commons.