170 PERMIAN FOSSILS 



Collywesten, and between Mar and Hickleton. Mr. Binney has collected specimens 

 at Hampole, in Yorkshire, and at Kirkby Woodhouse, Notts. Count Miinster records 

 its occurrence at Gliicksbrunn ; and it is probably found at most of the other German 

 localities noticed under the last species. M. de Verneuil has procured it in the 

 Permian rocks of Tioplova, Kliutziski, Pinega, Itschalki, and Barnoukova, in Russia ; 

 and in the Carboniferous deposits at Mala, Jaroslavetz, and near Vitegra. Count 

 Keyserling found specimens in the Permian Limestone on the Wytschegda, near Ust- 

 Nem, and on the Wymra, in Petschora-land. Count Miinster records its occurrence 

 in the Trias (?) Marls of St. Kassian. 



Bakevellia tumida, King. Plate XIV, figs. 35, 36, 37. 



(?) Small species of Modiola, J. de C. Sow. Trans. Geol. Soc. Lond., 2d series, vol.iii, 



p. 119, 1829. 

 Gervillia (?) TUMiDA, Kiriff. De Verneuil, Bull. Soc. Geol. de France, 2™' serie, I. i, 



p. 35, 1844. 



— — „ Geol. Russ., vol. i, p. 225, 1845. 



— — „ Tennant, Strat. List, p. 88, 1847. 

 Bakevellia — ,, Catalogue, p. 10, 1848. 



AvicuLA INFLATA, Brown. Howse, Trans. T. N. F. G., vol. i, p. 250, 1848. 



Diagnosis. — Modioliform : longer than wide, the length being half an inch, and the 

 width a quarter. Valves convex ; (?) smooth. Unibones divaricated ; slightly incurved. 

 Anterior lobes distinct. Posterior wings very slightly produced. Hinge-areas large ; 

 with four or five cartilage-pits. Byssal or pedal sinus rather large in the under valve. 



This is a well-marked shell, easily distinguished from the former two species, even 

 the most tumid variety (= Avicula itijlata, Brown) of Bakevellia antiqua, in being longer 

 than wide, and in the greater divarication of the umbones. It also appears to be a 

 smaller species. 



Bakevellia tumida occurs rarely at Tunstall Hill and Dalton-le-Dale, and rather 

 commonly at Humbleton Quarry and Ryhope Field-House Farm, in Shell-limestone. 



Bakevellia bicarinata, King. Plate XIV, figs. 41, 42. 

 Bakevellia bicarinata, King. Catalogue, p. 10, 1848. 



Diagnosis. — " Nearly smooth, winged, and furnished with two faint ridges on its 

 anterior lobes.^' (King.) 



This species, which I have elsewhere supposed to be a variety of one of the 

 former species, is somewhat intermediate in form to Bakevellia ceratophaga and Bake- 

 vellia antiqua ; though evidently more related to the former.^ Its ridges diverge (vide 



1 Catalogue, p. 10. A mistake was made in stating that Bakevellia bicarinata "may be a variety of 

 B. antiqua : B. ceratophaga was intended for the last species. 



