(4) 



(5) 



(6) 



70 , 



, 72 



71 mm. 



59 



. 63 



• 59 „ 



114 CRETACEOUS LAMELLIBRANCHIA. 



? 1865. Astarte obovata, H. Coauand. Mon. Aptien de l'Espagne, p. 122, 



pi. xiii, figs. 3, 4. 

 1866. — — F. J. Pictet and 0. Campiche. Foss. Terr. Out. Ste. 



Croix (Mater. Pal. Suisse, ser. 4), p. 312. 

 1871. (Erypuyla), F. Stoliczka. Palseont.Indica, Cret. Fauna, 



S. India, vol. iii, p. 285. 

 1892. — 0. Behrendsen. Zeitschr. d. deutsch. geol. Gesellsch., 



vol. xliv, p. 22. 



Description. — Shell large, oval, transverse, moderately inflated, very inequi- 

 lateral. Anterior margin rounded, concave in front of the umbo. Behind the 

 umbo the dorsal margin has a gentle and regular curve. Posterior margin rounded 

 or sub-truncate. ITmbones prominent, curving forward. Lunule deep. Escutcheon 

 narrow, deep. 



Ornamentation consists of numerous, strong, close, somewhat irregular concentric 

 ribs, on which fine, concentric, linear ribs occur. 



Measurements : 



(i) (2) (3) 



Length . . 75 . 74 . 73 

 Height . . 62 . 58 . 60 



(1-4) Perna-bed, Atherfield. 

 (5, 6) Pema-bed, Sandown. 



Affinities. — Astarte Beaumonti, Leymerie, 1 and A. transversa, Leymerie,- are 

 closely allied to A. obovata, and were regarded by Forbes as merely varieties of the 

 latter. Pictet and Renevier (1857) were inclined to regard the differences as not 

 of specific importance. Pictet and Campiche (1866), however, kept the three forms 

 distinct, but were uncertain whether they should be regarded as species or varieties. 

 They state that in A. Beaumonti the margin is smooth, whilst in A. obovata and 

 A. transversa it is crenulated. In the first two forms the posterior margin is more 

 rounded, but in the last it is more truncate. It is very doubtful whether the 

 crenulation of the margin is a feature of specific importance in Astarte ; indeed, 

 one writer 3 thinks that it is a characteristic of sex. Whether the other differences 

 are of specific value can be determined only by the comparison of a number of 

 examples of A. Beaumonti and A. transversa with specimens of A. obovata. 



1 'Mem. Soc. geol. de France,' vol. v (1842), pp. 4, 24, pi. iv. fig. 1. D'Orbigny, 'Terr. Cret.,' 

 vol. iii (1844), p. 60, pi. cclx. Pictet and Campiche, 'Terr. Cret. Ste. Croix' (1866), p. 300, pi. cxxiv, 

 fig. 1. Wollemann, ' Biv. u. Castrop. d. deutsch. u. holliind. Neocoms ' (1900), p. 95. 



2 Op. cit. (1842), pp. 4, 24, pi. v, fig. 5. D'Orbigny, op. cit., p. 61, pi. cclxi. Pictet and Campiche, 

 op. cit., p. 301, pi. cxxiv, fig. 2. De Loriol, ' Anim. Invert. Foss. Mt. Salcve ' (1861), p. 68, 

 pi. viii, fig. 9. 



:! A. Ostrooumoff, 'Zool. Anzeiger,' vol. xxiii (1900), p. 499. 



