Fig. 7
Centrostephanus longispinus (Philippi), USNM E20008, SE micrographs of broken sections through primary spines. a Stub B7, broken base of a spine. b Stub B7 (different specimen from a, c), broken tip of a spine. c Stub B7 (different specimen from a, b), broken tip of a spine. d Stub B8, broken base of spine. e Stub B9, broken base of spine. f Stub B9 (different specimen to e), broken tip of spine. All scale bars represent 500Â ÎĽm except a which represents 300Â ÎĽm