122 FOSSIL OOLITIC ASTERIAD^E. 



D. — Species from the Forest Marble. 

 AsTROPECTEN Phillipsii, Forhes. PI. X, fig. 2, a, b, c, d, e. 



AsTKOPECTEN Phillipsii, Forbes. ]\Iemoirs of the Geological Survey of Great Britain, 



vol. vi, part 2, p. 4/8, 1848. 



— — Forbes. Ibid., British Organic Remains, decade 1st, pi. ii, 



fig. 2, 1849. 



— — Wright. British Association Reports, vol. for 185G, p. 402. 



Rays five, elongate, lanceolate ; margins straight ; intermediate angles obtuse ; mar- 

 ginal plates quadrate, and transversely elongated, surface tuberculated, the tubercles 

 supporting short, stout spines. 



Dimensions. — Diameter of the body from ray point to ray point, about five inches ; 

 diameter of the disc, one inch and one sixth ; breadth of a ray at the base six tenths 

 of an inch. These measurements are only approximate, as the specimen is slightly 

 distorted. 



Description. — Disc moderately developed, the arms being in length, compared with its 

 diameter, as one and three quarters to one. 



Rays slender, lanceolate, forming very obtuse angles at the junction with each other 

 and the body. Margins of the rays bordered with oblong quadrate plates, which are 

 studded with small tubercles, probably marking the points of attachment of paxillse; on 

 their edges also are a few scattered linear-lanceolate spines, which are not equal to the 

 breadth of the plate. The ambulacra are bordered with semicircular combs of short 

 spines. 



The plates composing the skeleton of the body appear to have been oblong. The 

 marginal plates at the angles are narrow, as compared with those of the ray borders. The 

 diameter of the body is about one inch and one sixth. The length of the rays appear 

 to have been about two and one sixth inches ; their breadth, near the junction of the 

 rays with the body, is about seven twelfths. 



Affinities and differences — This beautiful species bears a striking resemblance to the 

 recent Jslropecten arantiacus, Lin., and its allies. No fossil species of this genus, as yet 

 figured, so clearly proves the true generic position of the extinct forms as this. 



Localiti/ and Strati (graphical Position. — This lithograph was executed from a drawing 

 by Prof. Phillips of a specimen obtained from the upper sandy beds of Forest Marble 

 at Ilinton-lane-end, Yorkshire ; fig. 2 « shows the under surface ; fig. 2 b the structure and 



