derma vs exocarp

derma

noun
  • The inner layer of the skin. 

  • A Jewish dish of roast or boiled seasoned meat and flour etc. in a casing, especially kishke. 

exocarp

noun
  • The outermost layer of the pericarp of fruits; the skin or epicarp 

How often have the words derma and exocarp occurred in a corpus of books? (source: Google Ngram Viewer )