mandible vs proboscis

mandible

noun
  • Any of various invertebrate mouthparts serving to hold or bite food materials. 

  • One of the anterior pair of mouthparts of an arthropod, designed for holding and cutting food. 

  • The jaw or a jawbone, especially the lower jawbone in mammals and fishes. 

  • Either of the upper and lower segments of a bird's beak. 

proboscis

noun
  • The tubular feeding and sucking organ of certain invertebrates like insects, worms and molluscs. 

  • The trunk of an elephant. 

  • A large or lengthy human nose. 

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