Fig. 9From: The internal morphology of primary spines of extant regular echinoids in the tropical western Atlantic: a SEM atlasGenocidaris maculata A. Agassiz, USNM E40228, SE micrographs of broken sections through primary spines. a Stub C1, oblique view of spine. b Stub C2, oblique view of spine fragment. c Stub C3, oblique view of spine fragment. d Stub C2 (different specimen from b), oblique view of broken spine. e Stub C3 (different specimen from c), oblique view of spine fragment. All scale bars represent 200 μmBack to article page