Assertion: mastodon's tusk | /r/HasProperty | lost
Facets:
Source sentences:
text: He argues that the genus Tetracaulodon was erroneous, founded upon dental appearances in the lower jaw of a very young proboscidian, and that Mr. W. Cooper was correct in suggesting that the Tetracaulodon was nothing but the young of the gigantic Mastodon, the tusks of which were lost as the animal advanced in age.