RHYNCHONELLA. 85 



and it is possible that the author of the ' Pal. Franc.' may have considered as belonging to 

 the same species, shells named B. parvirostris and B. Gibbsiana, which appear with us 

 distinct, and peculiar to the Lower Green Sand (Neocomien of the French). 



The figures published by Viscomte D'Archiac of his Bh. Scaldinensis entirely agree 

 with our typical examples of B. latissima, and much more closely so even than the figures 

 he attributes to the Sowerby species. The celebrated author of the ' Histoire des Progres 

 de la Geologie,' mentions that his Ter. Scaldinensis numbers as many as 65 plaits, while 

 Sowerby only mentions 40 to his B. latissima, but from what I have said above, it may 

 be seen that the plaits in our British species vary very much, and are often as numerous 

 as in B. Scaldinensis of the French author. 



Plate XI, figs. 6, 7, 8, and 14. Different specimens and shapes of B. latissima, from 



the Upper Green Sand of Warminster. 

 ,, figs. 9, 10, 11. Young specimens, from same locality. 



,, fig. 12. Unsymmetrical and aged example, same locality. 



„ fig. 13. Amalformation,fromWarminster,fromthe cabinet of Mr. Cunnington. 



,, fig. 15. A ventral valve from Farringdon. 



„ fig. 16. A convex variety, same locality. 



,, fig. 17. Profile and front view of another Farringdon specimen, in the 



collection of Mr. Lowe. Fig. 17 c , an enlarged illustration, to 

 show exactly the complex condition of the plaits. 

 „ fig. 18. A young specimen from Farringdon. 



,, figs. 19 and 20. A specimen from the same locality, in the collection of Mr. 



Lowe, in which the complex plication above described 

 is well exemplified, and especially so in the enlarged 

 figure 19 c . 

 ,, figs. 21 and 22. Two other examples from the same locality, in the collection 



of Mr. Sharpe. B. Antidichotoma, Buv. ? according 

 to Mr. Sharpe. 

 Plate XII, fig. 24. A very remarkable example, from the Chloritic Marl of Ohardstock, 



in the collection of Mr. Wiest. 



38. Rhynchonella sulcata, Parkinson, Sp.? Plate X, figs. 18 — 36. 



Terebratula sulcata, Parkinson. Trans. Geol. Soc, vol. i, p. 347, 1811, and vol. v, 

 p. 57, 1821 (but neither figured nor described). 

 — — Morris. Catalogue, 1843. 



Rhynchonella sulcata, UOrbigny. Pal. Franc., Ter. Cretaces, vol.iv, p. 36, pi. 495, 



figs. 1—7, 1847. 



Diagnosis. Shell transversely oval, wider than long ; valves more or less unequally 

 convex, ventral or dental valve in general the deepest, with a shallow longitudinal sinus 

 to which a moderately produced mesial fold corresponds in the opposite one. Beak short, 



