METOPASTER SUBLUNATUS. 51 



this fossil, and the radial dimensions can only be calculated approximately. The 

 specimen figured by Forbes, which I have unfortunately not been able to trace, is 

 smaller than either of the above. The drawing represents a test with the major 

 radius measuring about 25 mm., the minor radius 20 mm., and the length of the 

 side about 28 mm. The figure of the actiual aspect of this example is reproduced 

 on PL XIV, fig. 3, of this memoir. 



Localifi/ and StratuirajMcal Position. — This is a well-known Upper-Chalk form. 

 It is recorded by Forbes from Kent, Sussex, and Wiltshire. Specimens in the 

 British Museum bear the localities of Charlton, Gravesend, Bromley, and 

 « Kent." 



History. — This species, primarily described by Forbes in his memoir ' On the 

 Asteriadae found fossil in British Strata,' was first figured in Dixon's ' Geology 

 and Fossils of the Tertiary and Cretaceous Formations of Sussex,' London, 1850. 

 The example which I consider must undoubtedly have been the type (Dixon, 

 pi. xxi, figs. 4 and 5) I have hitherto unfortunately not been able to find. It is 

 stated by Forbes to have formed part of the late Mr. Pearce's collection, and to 

 have been obtained from the Wiltshire Chalk. A badly drawn fragment (Dixon, 

 pi. xxi, fig. 8) is preserved in the British Museum, but I do not consider it to be 

 correctly referred to this species. In my opmion it belongs to a distinct species, 

 Metojiaster cingulatus, of which a description is given at p. 53. 



The examples of this species which have been drawn on PI. XIV are preserved 

 in the British Museum. 



6. Metopaster SUBLUNATUS, Forbes, sp. 



GoNiASTEE (GoNiODiscus) SUBLUNATUS, Forbes, 1848. Memoirs of the Geological 



Survey of Great Britaia, vol. ii, 

 p. 472. 



— — — Forbes, 1850. In Bison's Geology and 



Fossils of the Tertiary and Cretace- 

 ous Formations of Susses, London, 

 4to, p. 331. 



— — — Morris, 1854. Catalogue of British Fos- 



sils, 2nd ed., p. 81. 

 AsTBOGONlUM SUBLUNATUM, Dujarditi and IIiipc, 1862. Hist. Nat. 



Zooph. Echin. (Suites a Buffon), 



p. 399. 

 GoNiASTEB (GoxioDiscus) SUBLUNATUS, Forbes, 1878. In Dison's Geology of 



Sussex (new edition, Jones), 



p. 365. 



