Remains of Echinoderms are so rare in the Hartwell Clay of Buckinghamshire, and when found so fragmentary, that it may be worth while drawing attention to a small piece of an Echinoid test recently obtained from the Hartwell Brick-pit by Mr. Edwin Hollis, F.Z.S., curator of the Aylesbury Museum, and presented by him to the national collection (Brit. Mus., Geol. Dept., E 12241). The terminology of the following description is that defined on pages 59–65 of my “Triassic Echinoderms of Bakony”, Budapest, 1909.