Slide showing tinted diagram of a 'Cross-section through larva of Bombinator' (toad) Slide shows tinted diagram of a 'Cross-section through larva of Bombinator' (toad). Diagram is labelled 'L.'' and 'L.' Blue tinted section is the proliferation of the primary lens-forming cells. Title below image reads 'Fig. 35. Cross-section through larva of Bombinator; operation as in Fig. 33. L., rudiment of normal lens; L.', proliferation of the primary lens-forming cells. (After Spemann, 1912a.)' Late 19th to early 20th century