ASTARTE. Ill 



less prominent, and the posterior end of the shell is rather more pointed. This 

 form resembles A. angulata, Gueranger. 1 



Types.— The types of A. laticosta came from the Neocomian of Chaource and 

 Jully (Aube). D'Orbigny's specimens of A. striato-costata were obtained from the 

 Neocomian of Marolles (Anbe), Attanconrt (Haute-Mame), and Saint- Sauveur 

 (Yonne). The specimens described by Forbes are in the Museum of the Geological 

 Society (No. 2181). 



Distribution. — Atherfield Beds of Peasmarsh and Sevenoaks. Perna-hed of East 

 Shalford, and probably Atherfield. Recorded by Topley from the Atherfield Beds 

 of Haslemere, and the Hythe Beds of Lympne. 



Astarte, sp. Plate XV, figs. 3, 4. 



Some specimens from the Folkestone Beds of Folkestone are very similar 

 to A. subcostata, d'Orbigny, but are larger, less elongate, and have a smaller 

 apical angle. 



Astabte Omalioides, sp. liov. [ex Gardner MS.]. Plate XV, figs. 5-7. 



Description. — Shell small, triangular or sub-quadrate, compressed, slightly 

 inequilateral, height and length nearly equal. Dorsal half of valves pointed. 

 Antero-dorsal margin slightly concave; postero-dorsal margin rather longer and 

 nearly straight, the remaining margin forming a regular curve. Umbones pointed. 

 Margins of valves finely crenulate. 



Ornamentation consists of a few (usually 6 or 7) prominent, sharp, concentric 

 ribs, with steep dorsal slopes and more gentle ventral slopes. Interspaces very 

 broad. The ribs become more distant from one another in passing from the umbo 

 to the ventral margin. A few very faint concentric ribs are sometimes present also. 



Measurements : 



(i) (2) (3) 



Length . 5"0 . -1'25 . 4-0 mm. 



Height . 4-75 . 4'25 . 4-0 „ 



(1—3) Gault, Folkestone. 



Affinities. — This species is closely allied to A. subcostata (see p. 109), but is 

 relatively shorter and less convex, and has a smaller apical angle and rather fewer 

 ribs. 



1 'Album Pak'ont, de la Sarthe ' (18G7), p. 13, pi. xvi, tig. 5. 



