14 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



I 



8. Thecidea Bouchardii, Dav. Plate I, figs. 15, 16. 



Diagnosis. Shell irregular, inequivalved, of an elongated transversal form, attached 

 by the greatest part of its lower valve ; area in larger valve long and straight, receding 

 from its junction with the upper valves, and at almost right angles to it ; deltidium well 

 defined, elevated, and marked by lines of growth, which extend also over the area ; upper 

 valve slightly convex, smooth, and strongly punctuated ; greatest height at hinge line 

 receding thence to the frontal margin. Interior of attached valve only known ; hinge line 

 straight, with two strong teeth and internal elevated mesial ridge, and wide, strongly- 

 granulated margin, leaving two deep depressions on each side of the central elevated 

 ridge. Length \\, breadth 2 lines. 



Obs. Three specimens of this species were found attached to the same specimen of 

 Bh. serrata, or along with Th. Moorei, and consequently from the middle lias, and I feel 

 much pleasure in dedicating it to M. Bouchard ; its locality is the neighbourhood of 

 Ilminster. M. Tesson, of Caen, showed me a specimen of Thecidea, which approaches this 

 very much in form, and is found in the liasic beds of Fontaine Etoupe Tour, near Caen, in 

 Normandy, and I should not have hesitated in saying it was the same species, had the 

 dimensions of the French specimen not exceeded three times those of our English shell. 

 Th. Bouchardii is easily distinguished from the other forms of this genus by its great 

 breadth, and appears a much more delicate species than either T. Moorei or T. triangularis. 



Plate I, fig. 15, natural size of a specimen in Mr. Moore's collection; figs. 15a, 16, 

 and 17, enlarged views. 



9. Thecidea Dickinsonii, Moore, MS. Plate XIII, fig. 19. 



Diagnosis. Shell of an elongated transversal form, unequivalved, and attached by the 

 greatest part of its lower valve ; area and cardinal edge straight, and not quite as long as 

 the greatest width of the shell; upper valve slightly convex, smooth, and punctuated. 

 Length 1^, width 2^ lines. 



Obs. This is the largest Inferior Oolite Thecidea, I believe, as yet known, and 

 is attached to a specimen of Ter. perovalis, from Dinnington, belonging to Mr. Moore, who 

 named it after his friend Mr. Dickinson. We find also, in the same locality, Thecidea 

 triangularis, which is easily distinguished by its shape. 



10. Thecidea Triangularis, D'Orb. Plate I, figs. 11, 12. 



Thecidea triangularis, D'Orb. (?) 1849. Prodrome, vol. i, p. 316. 



Diagnosis. Shell irregular, inequivalved, attached by the greatest portion of its lower 

 valve, more or less triangular, gibbose, produced behind, and somewhat bilobate in front ; 



