The Echinoid Directory

Fasciole arrangements


Peripetalous fasciole On aboral surface, running round the ends of the petals	Lateroanal fasciole Running from behind the anterior petal and passing laterally beneath the periproct. Always associated with a secondary peripetalous element	Internal fasciole Bounding the anterior ambulacrum but not the paired petals

Subanal fasciole At the rear of the plastron immediately beneath the periproct. Either lozenge-shaped or bilobed	Lateral fasciole Passing around the ambitus and beneath the anus at some distance from the tips of the petals	Pseudolateral fasciole Ambital in position but passing above the periproct and thus a modified peripetalous fasciole