208 SUPPLEMENT TO THE BRITISH 



which had been procured from an ochraceous limestone (Inferior Oolite) at Cleeve Hill, 

 near Cheltenham. 



210. Far. sub-angulata, Dav. Sup., PI. XXIX, figs. 14, 15, 16. 



This variety occurs abundantly in the Pea-grit (Inferior Oolite) at Leckhampton 

 Hill, and in the same formation at Bradford Abbas, in Dorsetshire. The mesial fold is 

 considerably more elevated than in the typical forms of Sowerby's species. When the 

 smaller valve of Rh. angulata is viewed in profile, it presents a regular convex curve, while 

 in the variety sub-angulata the same valve in profile is almost straight or very slightly 

 convex, and is even a little bent upwards near the front, as in Rh. varians. It is also more 

 sub-pentagonal, and broader than long ; the hinge-line presents a long and very obtuse 

 angle. From twenty to twenty-four angular ribs cover each valve, of which three or four 

 occur on the fold and sinus, these last being somewhat larger or stronger than those on 

 the lateral portions of the valve. An average-sized example measured — 



Length 8, width 10, depth 6 lines. It seems to be pretty constant in shape. 



211. Rhynchonella variabilis, Schloth. Dav., Ool. Mon., p. 78, PI. XV, figs. 



8—10. 



Palaeontologists seem to differ considerably in their views with respect to this species. 

 There can, however, exist no uncertainty with regard to the small shells we have figured 

 (figs. 8, 9, 10), for they agree in shape, size, number of ribs, and every other particular, 

 with the specimen figured by Schlotheim in c Leonhard's Mineral. Tasenbuch.' for the year 

 1813. Schlotheim's figure, as well as ours, shows that the ribs composing the mesial fold 

 are slightly turned upwards close to the margin, as is seen in figs. 9 and 10 of our plate. 

 Now, this feature is rarely observable, as far as I am aware, in the larger shell to which 

 Young and Bird gave the name of T. lineata, and Phillips those of T. bidens and 

 T. triplicata. Dr. D. Brauns, in his valuable work ' Der unter Jura im norwestlichen 

 Deutschland,' p. 436, 1871, gives a very long list of synonyms, but I fear few are 

 applicable to the species under description. 



Rhynchonella variabilis, thus restricted, was first found by myself in the Lias near 

 Radstock, and subsequently by Mr. E. B. Tawney in the same neighbourhood. He 

 also quotes it from the Lower Lias (' Bristol Naturalists' Society ' Proceedings, vol. i, 

 part 2, p. 189, 1871). 



