This is the ninth of 43 appearances Arthur Space makes in the series, each time appearing as Doc Weaver, the local veterinarian. In season two, he took over for Doc Peter Wilson, played by Frank Ferguson, who appears in that role only in season one.
This is the only appearance Howard McNear makes in the series, playing his signature comedic role as the easily befuddled, slightly disoriented character that endeared him to viewing audiences in the '50s and '60s, especially in the recurring role as Floyd Lawson, the barber, in the 1960s TV sitcom The Andy Griffith Show (1960).
Professor Scott mentions the Pleistocene Epoch in relation to the discovery of the bone. This geological time period occurred roughly between 3 million years ago and 11,000 years ago and is commonly referred to as the Ice Age.