TEREBRATULA. 35 



28. Terebratula carinata, Lamarck. Plate IV, figs. 11 — 17. 



Terebratula carinata, Lamarck. Anim. sans. Vert., vol. vi, p. 25. 



— — Tennant. 1847. Stratigrapliical List of British Fossils, p. 73. 



— — Bronn. 1849. Index Palseont, p. 1232. 



— — Dav. 1850. Lamarck's Species of Fossil Terebratulse, Ann. 



and Mag. of Nat. Hist., vol. v, 2 de Serie, pi. xiii, fig. 25. 



Diagnosis. " T. testa subquadrangulari leevi ; valvd inferiori subcomplanatd superiore 

 diedrd medio-carinatd." — (Lamarck.) 



Shell inequivalved, oblong, longer than wide, smooth, surface punctuated. Perforated 

 or rostral valve convex with slightly recurved beak, lateral ridges continued along the sides 

 without recurving to join the hinge margin, foramen of moderate size, entire and separated 

 from the umbo by a rather long deltidium in two pieces ; imperforated valve regularly and 

 gently compressed almost from the umbo ; front sometimes considerably thickened. Loop 

 long and attached only to Crura: average dimensions; length 13, width 9, depth 5 or 6 

 lines, some specimens measuring, length 20, breadth 17, depth 10 lines. 



Obs. This species, established by Lamarck, in 1819, is distinguished from T. resupinata 

 by its rounder and less recurved beak, larger foramen generally separated from the umbo 

 by a greater distance and larger deltidium : it is also flatter and is a more elongated shell. 

 The depression of the imperforated valve is not the same in all specimens, some such as 

 those figured 13, 14, from Mr. Bowerbank's Collection, are almost convex, presenting a 

 depression only towards the front. The thickening or emargination of the valves is very 

 great in some specimens, as may be observed in fig 12, preserved in the Collection of 

 the Geological Survey. This species occurs in the Inferior Oolite near Stroud, Burton 

 Radstock, Dinnington, &c.; and fine specimens are to be seen in the Collections of Messrs. 

 Bowerbank, Morris, Moore, Walton, &c. In France it is found in the Inferior Oolite round 

 Caen in Normandy. In the Inferior Oolite of Chalford, near Stroud, and Crichley Hill, near 

 Cheltenham, a very wide and large variety of this species is found; figs. 15, 16, and 17, 

 remarkable from the size of its foramen ; the lateral ridges are also much nearer to the 

 umbo and thrown off from the fore part of the beak opening. I do not believe we could be 

 justified in separating this variety from T. carinata, as the above distinctions are not per- 

 manent, but varying in many specimens. Of this variety many fine specimens are to be 

 seen in the British Museum, as well as in the Collections of Messrs. Morris, Buckman, 

 Dr. Wright, &c. 



29. Terebratula emarginata, Sow. Plate IV, figs. 18 — 21. 



Terebratula emarginata, Sow. Min. Con., 1825, vol. v, p. 50, pi. 435, fig. 5. 



— — Deslongchamps. 1837. Soc. Linn, de Normandie. 



— — Morris. 1843. Catalogue. 



— — Bronn. 1849. Index Palseont., p. 1236. 



— — D'Orb. 1849. Prodrome, vol. i, p. 287. 



