TEREBRATULA. 65 



/ 



Terebratula semiglobosa, Schlotheim. System Vers., No. 80, 1832. 



— V. Buck. Classification des Terebratules Mem. Soc. Geol. 



de France, vol. iii, p. 205, pi. xix, fig. 9, 1834. 



— subundata, Deshayes. Nouv. Ed. de Lamarck, vol. vii, p. 333, No. 13, 



1836. 



— semiglobosa, Hisinger. Leth. Suec, p. 82, pi. xxiv, fig. 2. 



— — Bronn. Leth Geog., pi. xxx, fig. 11, p. 657, 1837, and 



Index Pal., p. 1250, 1848. 



— — jyOrbigny. Pal. Franc., Terrains Cretaces, vol. iv, p. 105, 



pi. 514, fig. 1—4, 1837, and Prodrome, vol. ii, p. 258. 



— — Brown. Illustrations of Fossil Conch., pi. liv, fig. 45-46, 



1838. 

 _ _ Geinitz. Char. Kreid., p. 16, 1839. 



— — Earner. Die Vers. Nord. Kreid., p. 43, No. 42, 1840. 



— albensis, Leymerie. Mem. Soc. Geol. de France, vol. iv, pp. 288, 289, 



1841 ; ii, p. 29, tab. xv, figs. 2—4, 1842. 



— semiglobosa, Leymerie. M6m. Soc. Geol. de France, vol. v, 1842. 



— — T. subrotunda, and T. subundata, Morris. Catalogue, 



1843. 



— — Reuss. Bohem. Kreid., pi. xxvi, figs. 5 — 8, 1846. 



— carnea, Reuss. lb., pi. xxvi, figs. 9 — 1 1. 



— bulla, J. de Sow. in Dixon. Geol. and Fossils of the Tertiary and 



CretaceoOs Formations of Sussex, p. 346, tab. xxvii, p. 11, 

 1850. 



— semiglobosa and T. albensis. A Catalogue of the Fossil Terebratulse 



in the British Museum, p. 25, 1853. 



Diagnosis. Shell variable in shape, inflated, circular, or elongated oval ; ventral or 

 dental valve, commonly the deepest, and uniformly gibbous ; beak short, more or less in- 

 curved, and perforated by a small circular foramen, contiguous to the umbone of the 

 opposite valve ; deltidium in two pieces, commonly inconspicuous ; beak ridges undefined ; 

 margins flexuous, straight, or bisinuated in front ; the dorsal valve is uniformly convex or 

 biplicated towards the frontal margin. External surface smooth, marked by concentric 

 lines of growth ; shell structure minutely punctate ; loop short and simple, not exceeding 

 a third of the length of the dorsal valve. 



Dimensions very variable : 



length 21, width 18, depth 1 5 lines ; 



' 



>> *■!.) ,, ■1-lj J, " JJ. 





1 3 11 7 





„ 16, „ 11, „ 11 „ &c 



Obs. In the first volume of the ' Mineral Conchology,' the names Ter. subundata 

 and T. semiglobosa, were proposed for varieties of a single form ; but most authors have 

 preferred the last denomination on account of its having been applied to the adult and 

 common condition in which the species is obtained. T. subundata is only a less convex or 

 more depressed variety, and it appears likewise, probable, that T. subrotunda of the same 

 author, may have been founded (at least in part) on a variety of T. semiglobosa; but 



