I'm-sure-there's-some-explanation

What About Dolphin Songs? 

Do you ever have trouble remembering the three categories of musical instruments of yore? This dolphin is here to help! They are: percussionalia (things you whack), tensibilia (things with strings), and inflatilia (wind instruments). 

Ninth-century manuscript of Cassiodorus, Institutiones. St. Gallen, Stiftsbibliothek, Cod. Sang. 855, p. 306 (www.e-codices.unifr.ch).