Schemes of Xenopus laevis tadpoles at developmental stage
50 and 54 in 'Individual images of Xenopus laevis tadpoles' (see references). These
drawings are low detail pictograms and lack characteristics for identifying a
particular developmental stage; they are therefore best used for illustrations that
require Xenopus tadpole icons. The file includes several versions of each
sketch, with various amounts of detail.
Edit 24 January 2017: Now there are additional schemes based on differently staged animals.