A distinctive spatangoid (heart-shaped) echinoid from the Grey Chalk.
1). Complete and uncompacted test (x2, Grey Chalk, near Cow Gap, Eastbourne, Randell Collection, RR1297). (A) View of the apical (upper) surface, anterior (front) end at the top of the image. (B) View of the oral (under) surface. The opening towards the anterior (bottom of the image) is the peristome.
2). Details of the above specimen (x1.5). (A) Posterior (rear) view. The central opening is the periproct. (B) Lateral (side) view, anterior end to the right. (C) Anterior (front) view. The opening bottom centre is the peristome.
3). Compacted test, which unusually retains a compliment of spines (Grey Chalk, Southerham Grey Pit, Lewes, Ross Collection, Booth Museum, by kind permission of John Cooper; (A) General view of the specimen (x2.7); (B) Detail of spines on the anterior margin (x8.2).
4). Detail of the above specimen showing the spines of the apical area (x7.7).