Slide showing tinted diagram of 'horizontal section through an embryo of Rana esculenta, the right eye of which has been covered by trunk epidermis of an embryo of Bufo.' Slide shows tinted diagram of 'horizontal section through an embryo of Rana esculenta, the right eye of which has been covered by trunk epidermis of an embryo of Bufo.' The far right side edge of the embryo is tinted blue. Title below image reads ' Fig. 42. horizontal section through an embryo of Rana esculenta, the right eye of which has been covered by trunk epidermis of an embryo of Bufo. In this transplanted epidermis a small lens has been induced. (After Filatow, 1925).' Late 19th to early 20th century