invaginate vs pull down

invaginate

verb
  • To turn or fold inwardly. 

  • To fold inward to create a hollow space where none had existed, as with a gastrula forming from a blastula. 

  • To fold up or enclose into a sheath-like or pouch-like structure, either naturally or as part of a surgical procedure. 

adj
  • Having one portion of a hollow organ drawn back within another portion. 

  • sheathed 

pull down

verb
  • To demolish or destroy (a building etc.). 

  • To make (something) lower (especially of clothes). 

  • To cause to fall to the floor 

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