congenerous vs selfsame

congenerous

adj
  • Having the same (kind of) origin or action 

  • Belonging to the same taxonomic genus; congeneric 

selfsame

adj
  • Chiefly preceded by the: precisely the same; the very same; the same not only in being similar but in being identical. 

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