- Ambulacrals generally compound, with two pores obliquely juxtaposed, in 2 columns as in all subsequent orders; interambulacrals usually with large radioles surrounded by smaller ones, as in Cidaroida, in 2 columns as in all subsequent orders, only one plate resorbed; mouth central, with jaws and external gills, sphaeridia present; anus aboral endocyclic. J.
'S ' --endocyclic jaws flat-reduced - lost branchiate ' 1 - lipobranchiat e sphaeridia exocyclic jaws loft y - abranchiate - ?
An anus is present either within the apical system (endocyclic, fig.
How would you define endocyclic? Add your definition here.