ASTARTE. 103 



One has the shell preserved, the others are internal casts showing- deep muscular 

 impressions. 



Types. — -Leymerie's specimens came from the Lower Neocomian of Avalleur, 

 Chenay, and Marolles (Aube). D'Orbigny records specimens from the Lower 

 Neocomian of St. Sauveur (Yonne). Pictet and Campiche figure specimens from 

 the Valanginian of Ste. Croix. 



Distribution. — Lower Greensand of Seend. 



Astarte subacuta, d'Orbigny, 1850. Plate XIV, figs. 4 — G. 



1844. Astarte carinata, A. d'Orbigny. Pal. Franc. Terr. Cret., vol. iii, p. 63, 



pi. cclxii, figs. 1-3. (non A. carinata, 

 Phillips, 1829.) 

 1847. — acuta, d'Orbigny. Ibid., p. 759. (non A. acuta, Reuss, 1846.) 



1850. — subacuta, d'Orbigny. Prodr. de Pal., vol. ii, p. 77. 



1866. F. J. Pictet and G. Campiche. Foss. Terr. Cret. Ste. 



Croix (Mater. Pal. Suisse, ser. 4), 



p. 318. 

 1900 — A. Wolleinann. Die Biv. u. Gastrop. d. deutsch. u. 



holh'ind. Neocoms (Abhandl. d. 



k. preussisch. geol. Land., N. F., 



pt. 31), p. 99. 



Description. — Shell triangular, much compressed, length greater than height, 

 slightly inequilateral. Antero-dorsal margin long and concave. Postero-dorsal 

 margin longer than the antero-dorsal, and either concave or nearly straight. Both 

 of these margins form obtuse angles with the well-rounded margin of the ventral 

 half of the shell. Umbones very acute, projecting, often nearly median and not 

 curved. Lunule narrow, with a sharp edge. Escutcheon very narrow. 



Ornamentation consists of prominent concentric ribs separated by broad inter- 

 spaces. The distance between the ribs increases in passing from the umbo 

 ventrally. Margins of valves crenulated. 

 Measurements : 



(i) (2) 



Length . 14 . 10 mm. 



Height . 11 . 8 „ 



(1, 2) Perna-hed, East Shalford. 



Affinities. — A. subacuta is distinguished from the other Cretaceous species by 

 its acute umbones and flattened valves. 



Remarks. — The only specimens which I have seen are in the Meyer Collection, 

 Sedgwick Museum. 



