20 EOCENE MOLLUSC A. 



Diameter, \\ inch. 



Locality. Stubbington {Edwards). 



In the beautiful work above referred to, now in course of publication by M. Deshayes, 

 the author gives not less than three varieties of this species, and the British fossil does not 

 differ in essential characters from one of the varieties of what is considered by the French 

 author to be a very variable shell. I have, however, placed the British fossil under that 

 name with a mark of doubt. 



6. Ostrea cymbuloidks, S. Wood. Tab. Ill, fig. 2, (I, b. 



Spec. Char. 0. testa ovato -oblong a, depressiusculd, v ah a infer lore radiatiin plicatd t plieis 

 rofundis, iuberculato-squamosis, subundulatis, bifidis ; ralvd superiorc plana ; marginibus 

 superne crenatis. 



Shell ovately oblong, slightly depressed ; inferior valve radiately plicated, with rounded, 

 rough, or tuberculated and bifurcated rays; margin crenulated all round in the lower 

 valve, with lateral crenations on the upper part of the flat valve. 



Longest Diameter, \\ inch. 



Locality. Heme Bay {Boicerbanfc) . 



Although this shell bears considerable resemblance to some of the forms of cymbula, 

 it cannot satisfactorily be referred to that species, being more regularly ovate in outline, and 

 more finely costated. It differs from Jlabellula in several characters, and it does not appear 

 to have the tendency to angularity or prolongation which that species exhibits ; it has also 

 more numerous rays. 0. divaricata, Lea, somewhat resembles this species, but that shell is 

 more inflated on what, in the Dimyaria, would be the siphonal region, and there is also, 

 apparently, a difference in the form of the muscle-mark ; this in our shell is large, reniform, 

 and somewhat pointed upwards, while in the American fossil it is semi-lunate. 



The British fossil appears to be rare. 



7. Ostrea dorsata, Deshayes. Tab. VI, fig. 2. 



Ostrea DOUSAfA. Desk. Coq. Foss. des Env. dc Par., vol. i, p. 35.1, No. 22, pi. 55, 



figs. 9 — 1 1 ; and pi. 64, figs. 1 — 4, var. j5 ; pi. 54, figs. 9, 10. 



— — Id. 2d edit., Lam., t. vii, p. 251, No. 42, 1836. 



— — J. Soicerby. Min. Conch., t. 489, fig. 2. 



— — Id., in Dixon, Geol. of Sussex, p. 174, 1850. 



— D 'Orbigny . Prod, de Palaeont., t. 11, p. 395, No. 1 139, 1850. 



— — Morris. Catal. Brit. Foss., p. 1/4, 1854. 



— — Desk. An. sans Vert, du Bassin de Par., t. 11, p. 102, 1860. 



Spec. Char. O. testa orbiculatd, utrinque gibbosd ; in medio plus minusve subangulatd, 

 eel seiitieylindraced ; valvd inferiore convexd, coitus irregulariter lamellosd ; valvd 

 xuperiore striata ; striis tenuibus, divaricatis, instructd ; marginibus superne crenulatis. 



