Buddhist Dictionary of Pali Proper Names by G P Malalasekera
Gajakumbha Jātaka
Gajakumbha Jātaka:The Bodhisatta was once a minister of the king of Benares.Noticing that the king was slothful,the Bodhisatta took a tortoise as an object lesson,showing him how the indolent came to misery.
The story was related in reference to a monk who was slothful regarding his duties.J.iii.139f.