"Spicules of Holothurians. The series 1-6 shows stages in the development of an anchor and a plate in a Synapta. The series A-E shows stages in the development of a wheel in Chiridota, a synaptid." -Thomson, 1916

Holothurian Spicules

"Spicules of Holothurians. The series 1-6 shows stages in the development of an anchor and a plate in…