Fig. 6

Astropyga magnifica (A. H. Clark), USNM E15541, SE micrographs of broken sections through primary spines. a, d Stub B4. a lateral view of large spine. d Proximal end of broken spine. b Stub B4 (different specimen from a), tip of slender spine. c Stub B6, broken distal tip of spine. e Stub B5, oblique proximal view of fragment. f Stub B5 (different specimen from e, h), distal tip of large spine. g Stub B6 (different specimen from c), proximal end of large spine. h Stub B5 (different specimen from e, f), distal tip of slender spine. All scale bars represent 500 μm except h which represents 300 μm