Data PolicyPublications | Persons | Institutes | Projects IMIS Photogallery » References Tetrapygus niger (apical system) Description Apical system: Four large anal plates cover the peroproct.Scale 3 mm. Author Schultz, Heinke JPG file - 144.63 kB - 1 003 x 1 026 pixels added on 2005-02-23238 viewsFrom reference Schultz, H. (2006). Sea urchins: A guide to worldwide sha... © 2005 Schultz, Heinke Click here to return to the thumbnails overview