Possible Clues:

• Man stood like extinct sort of elephant
• Initially severe trouble filling in chap's old jumbo
• One building giving shelter to own very old elephant
• Extinct creature
• Large extinct animal resembling elephant
• Extinct 'elephant'
• Extinct mammal revealed by degrees to professor?
• Prehistoric creature stood trembling, trapped by homo sapiens
• Huge animal? Fellow stood shaking inside
• Graduate'll assume extinct large animal