170 CRETACEOUS LAMELLIBRANCHIA. 



? 18U8. TuETis MAJuit, .1. Briarl and F. L. Curnel. Muulu de l>rac<|uei,'uii.'i5 (Mi'in. 



cour. et Mt'ui. des Sav. L'traugers, vol. 

 xxxiv), p. 83, pi. vii, figs. 14, 15. 

 1871. FiJiuiuELLA LJiviGATA, F. Stol icxJcti. Palicout. Iiidica, Cret. Fauua S. 



ludia, Vol. iii, p. 24G. 

 1882. Thetis majob, P. de Loriol. Gault de Cosue, p. (Jl, {A. viii, figs. 6 — 8. 

 rl874. — — W. Daiiu'g. Zeitschr. d. deutsdi. geol. Gesellscb., vol xxvi, 



p. 7(3(3, pi. xxi, fig. 4. 

 1885. — — F. Nutlinij. Die Fauna d. baltiscli. Ceuomau. (Palscout. 



Abliaudl., vol. ii), p. 2'J, pi. v, fig. (3. 



Non 1845. — Sowerbii var. li majuk, E. Furbcs. Quart. Joiu-u. Geol. Soc, vol. i, 



p. 242. 



— 1846. — majok, ^1. d'Orhlijiiy. Pal. Frauc,'. Terr. Cn't., vol. iii, p. 454, vol. 



ccclxxxvii, figs. 8 — 10. 



— — — LasviGATA, d'Orbiijni/. Ibid., vol. iii, p. 452, pi. ccclxxxvii, figs. 1 — 3. 



— 1850. — — d'Orblymj. Prodr. de Pal, vol. ii, p. 118. 



— — — MAJOR, d'Orhhjnij. Ibid., vol. ii, p. 160. 



V — 1852. — SowERBYi, ii'. JiHtr. Deuksclir. d. k. Akad. Wissenscli. Wieii, Math.- 



uat. CI., vol. iii, p. 311, pi. xvi, fig. 21. 

 'i — 1868. — MAJOK, E. V. Eichwald. Letha;a Kossica, vol. ii, p. 708. 



Mi'iisiircmciitft : 



(1) (L-) (:!) (.1.) (5) ((!) 



Length . 47 -1-2 -11 o9 30-5 29-5 

 Ht'iglit . 43 40 39 37 27 28 



(1—10 Blackdowu. 



Ajjinitirs. — This species is closely allied to 1\ minor, with which it was uiiitcil 

 liy ll(")iiiei- under the name T. Soiccrlni, but it possesses relatively higher and 

 narrower uniljones than T. minor. T. laivijata is commonly of larger size than 

 T. mJiKir, and as in the case of the latter, the large forms are more inequilateral 

 than the small I'urms. A ratlier small example was figured by Sowerby as ('orlmhi 

 Iciivvjiilii, ami Avas taken l)y Stoliczka as the type of a new genus Fimbriella, but it 

 pi'oves to be, as was suggested by Pictet and Cam])iche, an example of 1\ viajur. 



The hinge can be seen in some specimens from Blackdown (Plate XXVI, figs. 

 19 A, 14). It consists of two small conical or tubercular teeth just below the 

 umbo of each valve. In the right valve the teeth are placed one above the other, 

 but the dorsal tooth is slightly in front uF the ventral and rather smaller than the 

 latter. In the left valve the teetli are side by side, nearly on the same level, 

 and the anterior tooth is rather larger than the posterior. Lateral teeth are 

 absent. The external ligament is short and prominent. 



Ti/pes. — The type of ('orhula ln'chjata, from Blackdown, and the types of 

 Thetis major, from Blackdown and Devizes, are in the British Museum. T. major 

 is the type of the genus Thetis, tSowerb}-. 



