112 CRETACEOUS LAMELLIBRANCHIA. 



Remarls. — Hince the name Omalioides has been used in stratigraphical lists, ^ it 

 seems desirable to retain it, although its construction is not in accordance with the 

 recommendations of the International Congress of Zoology. 



Distribution. — Gault (zones vii, x, and xi) of Folkestone. 



AsTABTE FOKMOSA, Soivevhi/, 183G. Plate XV, figs. 8-13. 



18-36. AsTARTE FORMOSA, /. de C. Sowerhy. Traus. Geol. Soc, ser. 2, vol. iv., pp. 



2.39, 341, pi. xvi, fig. 16. 

 1842. — — F. Bomer. De Astartarum Genere, p. 21. 



1850. — —A. d'OrhHjny. Prodr. de Pal., vol. ii, p. 160. 



1854. — —J. Morris. Cat. Brit. Foss., ed. 2, p. 186. 



1871. — — F. Sfoliczka. Palaeont. Indica, Cret. Fauna S. India, vol. 



iii, p. 285 (:'' Gouldia). 



Nou 1842. — — H. B. Geiiiitz. Char. d. Scbicht. u. Petref. des sachs.- 



bohm. Kreidegeb., pt. 3, p. 7G, pi. x.\i, 

 fig. 19 (see Geinitz, Elbthalgeb. i, i>. 

 227). 

 — 1844. — —A. d'Orhi(jnij. Pal. Franf. Terr. Cre't., vol. iii, p. 65, j.l. 



cclxii, figs. 10 — 12 {A. siihformusa, 

 d'Orb., 1850). 



Description . — Shell small, rather convex, sub-triangular, moderately inequilateral. 

 Antero-dorsal margin slightly concave. Anterior and ventral margins forming a 

 regular curve. Posterior margin less curved, often truncated, and forming an 

 obtuse angle with the long and slightly convex postero-dorsal margin. Uml^ones 

 pointed. Lunule large, ovate, depressed, smooth, with a sharp border. Escutcheon 

 long, lanceolate, depressed, smooth, with a sharp border. Margins of valves smooth. 



Ornamentation consists of strong concentric ribs with sharp summits, separated 

 l)y broad concave interspaces. The rilxs end abi'uptly at the margins of the linuilf 

 and escutcheon. On the riljs and interspaces fine concentric ridges may be seen. 



Measurements : 



(1) (2) (3) (4) 



Length . 5-0 . 475 . 4-5 . 4-0 

 Height . 4-5 . 4-5 . 4-0 . 3-75 



(1 — 6) Blackdown. 



Affinities. — A.furniosu is smaller and has more numerous ribs than A. suhfurnwsa, 

 1 Price, ' The Gault ' (1879), p. 58 ; Jukes-Browne, ' Cret. Eocks of Britain,' vol. i (1900), p. 465. 



