TEREBRATULA. 31 



24. Terebratula Waterhousii, Dav. Plate V, figs. 12, 13. 



Diagnosis. Shell inequivalved, longer than wide ; imperforated valve convex ; beak 

 small, rounded, and truncated by an entire foramen, with acute lateral ridges continued 

 along the sides, without recurving to join the hinge line ; deltidium in two pieces ; imper- 

 forated valve convex, except towards the front, where there is a concave depression, distinctly 

 bent downwards, giving the frontal line an indented appearance ; loop attached only to 

 the crura, and extending to near the frontal margin of the shell. Length 9, width 7, 

 depth 6 lines. 



Obs. This species, although distinct, comes near to Ter. cornuta by the form of its 

 beak, approaching those varieties in which the lateral prominence is not developed ; it 

 differs, however, in having the front distinctly bent downwards, as is seen in Plate V, 

 figs. 12«, 13«. Its greatest thickness is about the umbonal portion; it varies much in 

 form and shape, as may be perceived by comparing fig. 12 with fig. 13. Ter. Waterhousii 

 belongs to the upper portion of the middle Lias, and was first found by Mr. Walton and 

 myself at Earington Gurney, near Radstock, along with T. numismalis rimosa, &c. 

 Dr. Krantz, of Bonn, sent me specimens of this species from Bonfingen, in Wurtemberg, 

 in which locality this shell acquires larger dimensions than those as yet found in England. 



25. Terebratula resupinata, Sow. Plate IV, figs. 1 — 5. 



Terebratula resupinata, Sow. Min. Conch., 1818, vol. ii, p. 116, t. 150, figs. 3, 4. 



— — Desk. 1836. Nouv. ed. de Lamarck, vol. vii, p. 360. 



— — Pusch. Polens Palseontologie, 1837, tafal iv, fig. 6. 



— — Phillips. Geol. of Yorkshire, pi. xiii, fig. 23, 1835. 



— — Deslong champs. 1837. Soc. Linn, de Normandie. 



— V. Buck. Mem. Soc. Geol. de France, 1838, p. 229, 



pi. xx, fig. 11. 



— — Morris. Catalogue, 1843. 



Bronn. Index Palseont., 1849, p. 1248. 

 B'Orb. Prodrome, 1849, vol. i, p. 239. 



Diagnosis. Shell inequivalved, oblong, longer than broad ; rostral valve convex, much 

 compressed and keeled ; beak small and incurved, almost touching the umbo, lateral ridges 

 acute and continued along the side, without recurving to join the hinge margin, false or 

 marginal area increasing in width at some distance from the beak ; foramen entire, remark- 

 ably small, with a wide obtuse deltidium, in two pieces, rapidly decreasing as it approaches 

 the small foramen, which it partly encircles. Imperforated valve, laterally convex, with a 

 deep central longitudinal groove and depression, extending from the umbo to the front, 

 which is considerably curved backwards and depressed. The marginal line is straight or 

 gently curved on leaving the hinge, till it attains about two thirds of the length of the 



