ectoderm vs peltry

ectoderm

noun
  • Outermost of the three tissue layers in the embryo of a metazoan animal. Through development, it will produce the epidermis (skin) and nervous system of the adult. 

peltry

noun
  • Pelts or skins, collectively; skins with the fur on them; furs. 

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