However, in the poem Hyndluljóð (Lay of Hyndla) the nine giantess mothers of Heimdall have different names including Gjálp and Greip and Járnsaxa which are known from other myths and are not specifically mentioned as sisters in the poem.
Three myths are described in the twelve stanzas and half-stanzas of Úlfr's Húsdrápa: Baldr's funeral, Thor fishing for Jörmungandr, the Midgard serpent, and Heimdall's fight with Loki for the Brísingamen.
Dumézil theorizes that these myths of Fenrir/Víðarr and Bali/Vishnu may have a common origin in an Indo-European God of spatiality, similar but distinct from the hypothetical framing or entry/exit God that spawned Janus and Heimdall.