PLATE IX. 



AsTROPECTEN CoTTEswoLDi^, BucJcman, 



From the Stonesfield Slate. 



Fig. 



1 a. AsTROPECTEN CoTTESWOLDi^, Biick., p. 116. Dorsal surface, natural size. 



b. Disc of this specimen, magnified to show the raadreporiform body with its radiating 



laminae, and the five prominent oblong bodies formed by the upper 

 portions of the ambulacral bones. 



c. Portion of the upper surface of a ray of another specimen, showing the extension of 



the ambulacral bones throughout the ray. 



d. Three marginal ossicula, magnified four times, showing the small granules on their 



convex surface. ' 



2 a. AsTROPECTEN WiTTSii, Wright, p. 120. Dorsal surface, natural size. 



b. Portion of the disc and ray, showing the madreporiform body and marginal plates 

 of this species, magnified three times. 



3 a. AsTROPECTEN CoTTEswoLDi^. Another specimen, with a wider disc. 



b. Portion of a ray magnified twice, showing the marginal plates, and the intermarginal 



ossicles. 



c. Two marginal plates, magnified four times. 



4. AsTROPECTEN CoTTESwoLDiiE. Another specimen, dorsal surface, natural size. 



