Srimad Bhagavatam says,
Mahārāja Barhiṣat — henceforward known as Prācīnabarhi — was ordered by the supreme demigod Brahmā to marry the daughter of the ocean named Śatadruti. Her bodily features were completely beautiful, and she was very young. She was decorated with the proper garments, and when she came into the marriage arena and began circumambulating it, the fire-god Agni became so attracted to her that he desired her company, exactly as he had formerly desired to enjoy Śukī. [4.24.11]
In the commentary for this verse, Srila Prabhupada gives the gist of this story:
The words śukīm iva are also significant, for the fire-god Agni became attracted by the beauty of Śatadruti while she was circumambulating the bridegroom Prācīnabarhi, just as he had previously been attracted to the beauty of Śukī, the wife of Saptarṣi. When the fire-god had been present long ago at the assembly of Saptarṣi, he was attracted by the beauty of Śukī when she was circumambulating in the same way. Agni’s wife, named Svāhā, took the form of Śukī and enjoyed sex life with Agni.
It is mentioned herein that Śukī was the wife of Saptarṣi. Who is he?
What is the full narration of this story, and where is it mentioned?