title: Treatise Online, no. 20, Part E, Revised, Volume 4, Chapter 2A: Introduction to the fossil hypercalcified chaetetid-type Porifera (Demospongiae).
abstract: 1 3 2 4 5 fiG. 1. Rigid aspicular skeletons in chaetetid sponges; 1, SEM of a longitudinal fracture of Merlia lipoclavidisca, an extant form, from La Catedral cave at a water depth of 12 m, Balearic Islands, Mediterranean Sea, 70 (adapted from Vacelet & Uriz, 1991, p. 172, fig. 2a, with kind permission of Springer Science+Business Media); 2, SEM of a longitudinal fracture of Acanthochaetetes wellsi, an extant form, locality not given, probably a cave at Anae (Continued on facing page.) fiG. 7. E
journal: Treatise Online