Cowell. Jataka.

Title: The Jataka; or, Stories of the Buddha's Former Births 
Series Editor: E. B. Cowell
Year: 1895-193

Volume 1, edited by Robert Chalmers
Volume 3, edited by H.T. Francis and R.A. Neil

For online editions, see the Freebookapalooza.

I will be adding additional stories from the jataka later:

Volume 1:
Cullaka-Seṭṭhi: The Business Begins with a Mouse

Volume 3:
Daddabha: The Flight of the Animals