Data PolicyPublications | Persons | Institutes | Projects IMIS Photogallery » References Hemiaster expergitus (apical system) Description The apical system is ethmophract: The posterior genital plates and the posterior ocular plates join each other.Specimen of 37 mm length. Author Mortensen, Theodor JPG file - 23.16 kB - 406 x 451 pixels added on 2009-02-23599 viewsFrom reference Schultz, H. (2009). Sea urchins II: Worldwide irregular d... © 2009 Mortensen, Theodor Click here to return to the thumbnails overview