METOPASTER CORNUTUS. 55 



measurements : — major radius, 20 mm. ; minor radius, 15"5 mm ; length of the 

 side, about 22 mm. The thickness of the margin is 7 mm. in a specimen whose 

 side is 23 "5 mm. 



Locality and Stratigraphical Position. — The specimen described above and 

 figured on PI. XIV, fig. 4 a, is from the Upper Chalk, near Bromley. It is 

 preserved in the British Museum, and bears the register-number " 46,770." Other 

 examples which I refer to the same species are also in the National Collection, 

 and one, if not more, was obtained from the same locality. 



Bemarls. — A fragmentary example which was figured in Dixon's ' Geology and 

 Fossils of the Tertiary and Cretaceous Formations of Sussex,' pi. xxi, fig. 8, and 

 was referred by Forbes to Goniaster (Goniodiscns) uncatus, now forms part of the 

 collection in the British Museum, and bears the registered number " E 2577." 

 This specimen appears to me to belong to the present species, and not to the true 

 Metopaster uncatus. I can scarcely think that Forbes would have intentionally 

 ranked the two forms as belonging to one species, and I have not thought it 

 needful on the sole grounds of this fragment having been figured to regard 

 Metopaster cingulatus as a dismemberment of Forbes' Metopaster uncatus. 



Metopaster cingulatus is readily distinguished from Metopaster uncatus by its 

 very short broad supero-marginal plates, by their more limited and more conical 

 tumidity, by their greater height as seen in the margin, as well as by their 

 difi'erent ornamentation. The ultimate plates are triangular, and do not present 

 the peculiar form characteristic of Metopaster uncatus. In many respects 

 Metopaster cingulatus appears to hold an intermediate position between Mitraster 

 rugatus and Metopaster uncatus. 



8. Metopaster cobndtds, Sladen. PI. XIV, figs. 5 a — 5 d. 



Body of small size. General form depressed. Abactinal surface slightly 

 concave, the extremity of the rays being directed slightly upward. Actinal surface 

 slightly convex. Marginal contour pentagonal, with the sides slightly lunate 

 and the extremity of the rays slightly produced. The major radius is proportional 

 to the minor radius as 100 : 74, the actual dimensions in the example described 

 being, major radius about 19 mm., minor radius about 14 mm. approximately. 

 The length of the side is 22*5 mm. The margin is moderately thick and 

 apparently well rounded. 



