92 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



characters of both the above-mentioned species, it has the beak, foramen, and deltidium 

 of concinna, but is distinguished from it by its plaits, which are fewer in number, much 

 larger, and deeper ; the valves are also nearly equally convex, which is not the character 

 of the Sowerby types. I propose naming it subobsoleta, as it may, perhaps, be a variation 

 of that form, although I have not found sufficient grounds to admit it to be such. 



Fig. 14 illustrates the largest specimen I have seen, from the collection of the British 

 Museum. 



86. Rhynchonella angulata, Soiv. Sp. Plate XVII, fig. 13. 



Terebratula angulata, Sow. Min. Conch., vol. v, 1825, p. 166, tab. 502, fig. 4, 



(placed there under the name of acuta, corrected after- 

 wards to angulata.) 

 — — Morris. Catalogue, 1843. 



_ _ Bronn. Index Pal., 1848, p. 1229. 



Rhynchonella angulata, D'Orb. Prodrome, 1849, vol. i, p. 286. 



Diagnosis. Shell transversely oblong, gibbose ; beak moderately produced ; foramen 

 not entirely surrounded by the deltidium, a small portion being completed by the umbo ; 

 valves ornamented by a variable number of plaits, from ten to twenty-five on each ; five or 

 six forming a moderately produced mesial fold, with corresponding plaits in the sinus ; 

 length 7, width 9, depth 6 lines. 



Obs. According to MM. D'Orbigny, Morris, Waterhouse, and other Palaeonto- 

 logists, this species is distinct from B. concinna ; it is shorter, more transverse, than that 

 shell, but I am not yet certain that it may not be a variety. Von Buch is, however, 

 mistaken, in placing it as a synonym of B. dcpressa, Sow. B. angulata is found in the 

 Inferior Oolite of Cleeve Hill, near Cheltenham ; the specimen figured in my plate is the 

 original type kindly lent me by Mr. J. de C. Sowerby. 



87. Rhynchonella Morierei, Dav. Plate XVIII, figs. 12, 13. 



Diagnosis. Shell somewhat triangular, longer than wide ; beak tapering to an acute 

 point not much recurved, under which is seen a small foramen entirely surrounded by the 

 deltidium, which separates it more or less from the umbo ; beak ridges well defined, 

 leaving between them and the margin a large flat, or slightly concave false area, which 

 indents considerably by a marked curve the corresponding margin of the umbo. Valves 

 moderately convex, ornamented by a variable number of plaits, from thirty-three to forty- 

 four on each valve, from seven to nine composing a well-defined mesial fold, the lateral 

 plaits proceed by a gentle curve downwards to the margin, giving the shell an elegant, 

 somewhat winged aspect. The sinus is moderately deep, with from six to eight plaits. 

 Length 17, width 15, depth 12 lines. 



