104 CRETACEOUS LAMELLIBRANCHIA. 



Tijpe. — From the Neocoraian of Brienne (Aiilje). 



Distribution. — Perna-hed of East Slialford. Atlierfield Beds of Sevenoaks. 



AsTABTE siNUATA, iVOrtngnij, 1844. Plate XIV, figs. 7 — 9. 



1844. AsTAETE SINUATA, A. (VOrhigtiij. Pal. Fran9. Terr. Cn't., vol. iii, p. G9, pi. 



cclxiv, figs. 1 — 3. 

 1850. — — (VOrliyny. Proclr. de Pal., vol. ii, p. 118. 



1856. — — F. J. Pktet and E. Renevier. Foss. Terr. Aptien (Mater. 



Pal. Suisse.ser. l),p. 89, 

 pi. X, fig. 3. 

 18GG. — — F. J. Pictet and G. Campiche. Foss. Terr. Crt't. Ste. 



Croix (Matur. Pal. 



Suisse, ser. 4), p. 311. 



1871. — — F. Stoliczka. Palocout. ludica, Cret. Fauua S. India, 



vol. iii, pp. 251, 285. 

 1895. — — G. Maas. Zeitscbr. d. deutsch. geol. GeseUsch., vul. 



xlvii, p. 261. 

 19U0. — — A. WoUemann. Die Biv. u. Gastrop. d. deiitsch. ii. 



lioUi'ind. Neoeoms (Abhaudl. d. k. 

 preussisch. geol. Laud., N.F., pt. 31), 

 p. 100. 



Deserijitiov. — Shell siib-quadi-ate, rounded ventrally, trniicated posterioi-ly, 

 longer than high, slightly or moderately inequilateral, much compressed. A furrow 

 extends from just behind the umbo to the sinuosity on the posterior margin, and 

 cuts off a triangular, flattened, postero-dorsal part of the valve. Antero-dorsal 

 margin nearly straight. Anterior margin rounded, passing gradually into the 

 curved ventral margin. Posterior margin with a sinuosity above the postero- 

 ventral ano^le. Postero-dorsal marg-in straiufht or slisfhtlv concave, lonsrer than the 

 antero-dorsal margin, and forming an angle with the posterior margin. Umbones 

 pointed, inconspicuous. Limule and escutcheon long, narrow, with sharp edges 

 which have tooth-like ^projections where the ribs end. 



Ornamentation consists of rounded, concentric ribs separated by shallow 

 furrows. The ribs are rather stronger on the posterior than on the anterior j)art 

 of the shell, and are sinuoiis where they cross the posterior furrow. Smaller i'il)s 

 arc present on the main ribs and furrows. 



Measurements : 



