LIMA. 49 



Affinities. — This form was referred by Sowerby (in Fitton) to the Senonian 

 species L. semisulcata, Nilsson, 1 but has been regarded by most later writers as 

 distinct from that species, and was named L. Fittoni by d'Orbigny. 



L. Fittoni differs, as a rule, from L. semisuleata in its smaller size, and in having 

 the ribbed area less extensive and much more asymmetrical in position, though 

 occasionally, however, it is nearly symmetrical. It also appears to differ in 

 having a relatively shorter hinge-line and less equilateral form. 



For the relation of L. Fittoni to L. Tombeclciana see p. 46. 



Type. — The type is Lima semisuleata, Sowerby (ncm Nilsson) from the Upper 

 Greensand of Blackdown. A specimen in the Bristol Museum is regarded as the 

 type, but does not agree very well with the figure. 



Distribution. — Upper Greensand (zone of Schloenbacliia rostrata) of Blackdown 

 and Haldon. Cenomanian of Axmouth (Bed 12 of Meyer), Dunscombe (Bed 10), 

 and Pinhay. 



Lima (Limatula) subjiquilateralis, d'Orbigny, 1847. Plate VII, figs. 16a, b, 17. 



1847. Lima sub^equilateralis, A. (VOrbigny. Pal. Franc. Terr. Cret., vol. iii, 



p. 558, pi. ccccxxiii, figs. 1 — 5. 

 1850. d'Orbigny. Prodr. de Pal., vol. ii, p. 167. 



1870. F. J. Pictet and G. Campiche. Foss. Terr. Cret. 



Ste. Croix (Mater. Pal. Suisse, 

 ser. 5), p. 169. 



1871. Radpla (Limatula) sub^equilateralis, F. Stoliczlca. Palseont, Indica, 



Cret. Fauna S. India, vol. iii, 

 p. 415. 



Description. — Shell oval, or rounded oblong, pointed at the umbones, nearly 

 equilateral, about twice as high as long, of moderate convexity. Anterior margin 

 less curved than the posterior. Ears equal, smooth, with pointed ends. 



Ornamentation consists of about 20 very narrow ribs separated by broad, 

 slightly concave, interspaces which are crossed by growth-lines. Ribs are absent 

 near the anterior and posterior margins. 

 Measurements : 



Length . . . . 10 mm. 



Height . . . . 19 „ 



Upper Creensand, Warminster. 



Affimities. — See Lima Dupiniana (p. 48) and Lima sp. (p. 52). 

 Remarks. — I have seen only two English examples of this species, both of 

 1 For references, see p. 51, footnote. 



