OSTRBA. 389 



1881. Ostrea acutirostris var. inflexa, Etheridge. Ibid., p. 14(3, pi. iii, 



figs. 7, 8. 



1888. — curvirostris, A. Peron. Hist. Terr, de Craie S.E. Bassin Anglo- 



Parisieu, p. 173 {partim). 



1889. — — 0. Gfrieperikerl, Senou. v. Konigslutter (Palseont. 



Abhaudl., vol. iv), p. Si, pi. ii, 

 fig. 1. 

 1891. — — J. Bijhm. Palseontograpliica, vol. xxxviii.p. 92, pi. iv, 



fig. 5. 



— acutirostris, Bllhrn. Ibid., p. 92, pi. iv, fig. 11. 



1894. — — B. Lundgren. Mollusk. i mammillatus och mucronata 



zonerna, p. 39. 



— — curvirostris, Lundgren. Ibid., p. 40. 



— — scaniensis, Lundgren. Ibid., p. 40. 



— — curvirostris, A. Hennig. Geol. Foren. i Stockholm ForhaudL, 



vol. xvi, p. 514. 



— — acutirostris, Hennig. Ibid., p. 514. 



1895. — curvirostris, F. Vogel. Holliindisch. Kreide, p. 5. 



— — acutirostris, Vogel. Ibid., p. 5. 



— — scaniensis, Vogel. Ibid., p. 6. 



1897. — incurva, A. Hennig. Eevis. Lamellibr. i Nilsson's "Petrif. 



Suecana," p. 11, pi. i, figs. 15, 17, 21 — 

 23, 25—28. 



— acutirostris, F. Notling. U. Cret. (Maestriclitian) Mari Hills 



(Palseont. Indica, ser. xvi, vol. i), 

 p. 37, pi. ix, figs. 1, 9. 



1899. — G. de Alessandri. Palseont. Italica, vol. iv, p. 198. 



1901. — curvirostris, H. Imlceller. Palseontograpliica, vol. xlviii, p. 37. 



— — acutirostris, Imlceller. Ibid., p. 37. 



? 1902. — — A. Quaas. Palseontograpliica, vol. xxx, 2, p. 184, 



pi. xxi, fig. 11. 



— — — E. Dacqnr. Ibid., p. 363. 



— incurva, J. P. J. Bavn. Mollusk. i Danmarks Kridtafl., I, Lamellibr. 



p. 112, pi. iii, fig. 4. 

 1906. — E.Bose. Senon. Cardenas (Bol. Inst. geol. Mexico, No. 24), 



p. 42, pi. i, fig. 5. 

 1908. ■ — curvirostris, A. Peron. Compte Kendu Assoc. Franc. Avanc. 



Sciences, vol. xxxvi (1907), p. 306. 



— — — M. Leriche. Ibid., p. 338 (partim). 



19U9. — incurva, W. Bogala. Bull. Intermit. Acad. Sci. Cracovie (1909), 



2, p. 691. 



Description. — Shell thin, usually higher than long ; its form very variable, 

 depending on the character and size of the attached surface. 



The left valve is flat when attached throughout to a flat surface ; concave when 

 attached to a convex surface ; convex when attached to a concave surface or 

 when attached to only a small object near the umbo ; irregular when attached to an 



51 



