Aganippe

Aganippe is the name of a fountain and the naiad (a Crinaea) associated with it in Greek mythology. Aganippe was the daughter of Ternessus. The well is in Boeotia, near Thespiae, at the base of the mountain Helicon. It was created by the hooves of Pegasus and was associated with the Muses as a source of poetic inspiration.
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[Greek] A nymph, the daughter of the river-deity Ternessus. She resides in the well Aganippe near Thespiae, at the base of the mountain Helicon in Boeotia. The horse Pegasus supposedly created this well with his hooves. This fountain was also dedicated to the Muses because it imparted poetic inspiration. Hence the Muses are sometimes called Aganippides.