妙法蓮華經玄義 6.110

6.110

闍陀伽者，說菩薩本曾為師子，受獼猴寄，攫脇肉貿猴子。於病世作赤目魚，施諸病者。或作飛鳥，救於泫溺，如是等無量本生，多有所濟，皆名闍陀伽也。

As for *jātaka*, it relates how the Bodhisattva in the past was a lion, and receiving a monkey's entrustment, tore flesh from his own flank to redeem the monkey's young; how during an age of pestilence he became a red-eyed fish to give to all who were sick; or how he became a bird to rescue those who were drowning. Immeasurable birth stories such as these, which brought vast benefit, are all named *jātaka*.