120 OOLITIC FOSSIL ASTER! AD^. 



" The exact geological position in which the specimen was found, is thus precisely fixed 

 as at the base of the Great Oolite beds and the summit of the Inferior Oolite beds, in a 

 stratum equivalent to and, in its general characteristics, I believe, identical with the Stones- 

 iield slate of Oxfordshire." 



AsTiioPECTEN WiTTSii, Wright. PI. IX, fig. 2 a, b. 



AsTROPECTEN WiTTSii, Wrght . British Association Reports, vol. for 18.56, p. 402. 



— — Wright. Monograph of Oolitic Echinodermata, p. 428, Pal. 



Soc, 1858. 



Body flat ; rays five, elongated, tapering to a blunt termination, border bulging at 

 the middle of the ray, intermediate angles acute, disc small in proportion to the body ; 

 dorsal marginal plates quadrate, elongated transversely ; upper surface of the disc and 

 arms between the border plates, convex and prominent. 



Dimensions. — Diameter of the body from ray point to ray point, two and a half inches ; 

 diameter of the disc from the outer side of one angle to the opposite, eleven twentieths 

 of an inch, extreme breadth of a ray, three tenths of an inch. 



Description. — This Star-fish resembles Astropecten Cotteswoldice in its general structure, 

 but differs from it so much in the proportionate smallness of the disc to the diameter of the 

 body and in the bulging of the rays that I have separated it from that more common form. 

 It may probably be found to be a variety of A. Cottesiooldice should connecting links 

 between the two forms hereafter be discovered ; in the mean time, however, I have 

 separated it from that species and dedicated it to my friend, the Rev. E. F. Witts, who first 

 discovered Star-fishes in the Stonesfield slate of the Cotteswold Hills. The disc is small in 

 proportion to the diameter of the body, in the ratio of one to five; the rays, five in 

 number, are nearly of the same width throughout ; the borders bulge slightly in the 

 middle, and they terminate in blunted extremities ; this is very apparent in the upper ray 

 of fig. 2 a, but still more so in the specimen now before me. The marginal plates are 

 quadrate, little elongated transversely ; the surface is covered wdth fine granules, and there 

 are about fifty plates around the border of the most perfect ray ; the intermarginal space 

 is convex and prominent, and the dorsal integument, with its numerous paxillae, appears 

 to be well preserved ; in this specimen (fig. 2 b), the disc exhibits five elevations, cor- 

 responding to the inner ambulacral bones, within which it is slightly depressed. The 

 remains of the madreporiform body, represented in the enlarged drawing (fig. 2 b), is seen 

 close to the angle of the base of the longest ray ; the intermediate angles are very acute, 

 and the border plates compactly arranged, without the moniliform appearance seen in 

 some allied species. 



