90 FOSSIL ASTEROIDEA. 



ornament otherwise is worn away. There are a few small granular inter- 

 marginalia. 



"With these plates is associated a large plate which appears to be a worn radial 

 or interradial of P. Boysii. 



Family— ASTROPECTINIDvE {Gray, 1840), emend. Sladen, 188(3. 



Phanerozonate Asteroids with large marginal plates bearing spines or spiniform 

 papilla?. Abactinal skeleton with true columnar papilla?. Actinal interradial areas 

 small, interradial plates when present spinose. Ambulacral plates short and more 

 or less compressed. Superambulacral plates present. Aproctuchous. Pedicellaria? 

 rarely present. 



GW,/s— ASTROPECTEN, G. F. Schulze, 1760. 



Adambulacral plates touching the infero-marginal plates along the ray. 

 Marginal and adambulacral plate not correspondent in length and number. Supero- 

 marginal plates more or less well developed. Marginal plates long and more or 

 less quadrate. Superior and inferior series subequal. 



Asteopecten, sp. PI. XXV, figs. 2, 2 a. 



Material. — There is one specimen in the Sedgwick Museum at Cambridge, which 

 looks like an Astropecten. It is figured on PL XXV, figs. 2 and 2 a. Practically 

 only the marginal plates are preserved. 



Description. — R : r : : 45 mm. : 15 mm. The interbrachial arcs are well rounded. 

 The supero-marginalia are remarkably uniform in size throughout the greater 

 portion of the ray. Their breadth is 4 mm. and length 17 mm. About thirty of 

 these are present from the inter radius to the extremity. At the apex of the ray 

 these plates are adjunct. The upper surface of each plate is rounded. 



The infero-marginalia are equal in size, opposite to, and, as far as one can 

 judge, similar in appearance to, the superior series. There is a distinct groove 

 between the two series. 



Locality and Stratigraphical Position. — Upper Greensand, Blackdown (?). 



