The Jataka, Vol. II, tr. by W.H.D. Rouse, , at sacred-texts.com
"Who is it with a mighty cry, etc."--This is a story which the Master told at Jetavana about one Kokālika. At this time we hear that there were a number of very learned Brethren in the district of Manosilā, who spoke out like young lions, loud enough to bring down the heavenly Ganges 2,  while reciting passages of scripture before the Community. As they recited their texts, Kokālika (not knowing what an empty fool he showed himself) thought he would like to do the same. So he went about among the Brethren, not however taking the Name upon him, but saying, "They don't ask me to recite a piece of scripture. If
they were to ask me, I would do it." All the Community got to know of it and they thought they would try him. "Friend Kokālika," said they, "give the Community a recital of some scriptures to-day." To this he agreed, not knowing his folly; that day he would recite before the Community.
He first partook of gruel made to his liking, ate some food, and had some of his favourite soup. At sundown the gong sounded for sermon time; all the community gathered together. The 'yellow robe' which he put on was blue as a bluebell; his outer robe was pure white. Thus clad, he entered the meeting, greeted the Elders, stepped up to a Preaching Seat under a grand jewelled pavilion, holding an elegantly carved fan, and sat down, ready to begin his recitation. But just at that moment beads of sweat began to start out all over him, and he felt ashamed. The first verse of the first stanza he repeated; but what came next he could not think. So rising from the seat in confusion, he passed out through the meeting, and sought his own cell. Some one else, a real scholar, recited the Scripture. After that all the Brethren knew how empty he was.
One day the Brethren fell a talking of it in the Hall of Truth: "Friend, it was not easy to see formerly how empty Kokālika is; but now he has given tongue of his own accord, and shown it." The Master entered, and asked what they were discussing together. They told him. He said--"Brethren, this is not the first time Kokālika has betrayed himself by his voice; the very same thing happened before;" and then he told them an old-world tale.
Once upon a time, when Brahmadatta was reigning in Benares, the Bodhisatta was born as a young Lion,  and was the king of many lions. With a suite of lions he dwelt in Silver Cave. Near by was a Jackal, living in another cave.
One day, after a shower of rain, all the Lions were together at the entrance of their leader's cave, roaring loudly and gambolling about as lions use. As they were thus roaring and playing, the Jackal too lifted up his voice. "Here's this Jackal, giving tongue along with us!" said the Lions; they felt ashamed, and were silent. When they all fell silent, the Bodhisatta's cub asked him this question. "Father, all these Lions that were roaring and playing about have fallen silent for very shame on hearing yon creature. What creature is it that betrays itself thus by its voice?" and he repeated the first stanza:
At his son's words the old Lion repeated the second stanza:
"Brethren," the Master added, "’tis not the first time Kokālika has betrayed himself by his voice; it was just the same before;" and bringing his discourse to an end, he identified the Birth: "At that time Kokālika was the Jackal, Rāhula was the young lion, and I was myself the Lion king."
45:1 Fausbøll, Five Jātakas, p. 45 (not translated); below, Nos. 188 and 189.
45:2 The Milky Way. See the Introd. Story to No. 1, above.