LIMA. 31 



Remarks. The chief character in which Lima farringdoueusis differs from 

 L. parallela seems to be in the possession of well-marked ribs over the whole of 

 the anterior area. It also differs from the majority of examples of L. parallela in 

 that the ribs only decrease in size to a very small extent in passing from the 

 anterior to the posterior part of the shell; and further, the shell is less inequilateral 

 than is usual in L. parallela. 



I am inclined to regard Lima farringdonensis as not more than a variety of 

 L. parallela, but without better material it is impossible to express a confident 

 opinion. Almost all the specimens seen are in the condition of internal casts in a 

 brownish ferruginous sandstone. 



Type. The figure given by Sharpe is taken from a gutta-percha cast of an 

 external mould. It was obtained from Seende and is preserved in the Museum of 

 the Geological Society. 



Distribution. Lower Greensand of Seende and Faringdon. 



LIMA (MANTELLUM) GAULTINA, nom. nov. Plate V, figs. 16 20. 



? 1827. PLAGIOSTOMA ELONGATA, /. de C. Sowerby. Min. Couch., vol. vi, p. 113, 



pi. dlix, fig. 2 (upper figure only). 

 1847. LIMA PARALLELA, A. d'Orbigny. Pal. Franc. Terr. Oct., vol. iii, p. 539, 



pi. ccccxvi, figs. 11 14. 



1850. d'Orbigny. Prodr. de Pal., vol. ii, p. 138. 



1855. G. Cotteau. Moll. Foss. de 1'Yonne, p. 101. 



1854. ELONGATA, J. Morris. Cat. Brit. Foss., ed. 2, p. 171 (partim). 



1875. A. J. Jukes-Browne. Quart. Jouru. Greol. Soc., vol. xxxi, 



p. 296. 

 1897. PARALLELA, R. B. Newton. Proc. Dorset Nat. Hist, and Antiq. Field 



Club, vol. xvii, p. 88, pi. iii, fig. 11. 



1900. E. T. Newton and A. J. Jukes-Browne. Cret. Rocks of 



Britain, vol. i, p. 449. 



Nou 1850. PLAGIOSTOMA PARALLELUS, /. de C. Sowerby in .F. Dixon. Greol. Sussex, 



p. 356 (p. 386, ed. 2), pi. xxviii, 

 fig. 16 (=L. elongata, Sowerby). 



Description. Shell rather compressed, sub-quadrangular or nearly oblong, very 

 oblique, much longer than high, rounded posteriorly ; antero-dorsal margin long 

 and nearly straight, almost parallel with the postero-ventral margin. Apical angle 

 about 100. Umbones pointed, close together. Ears of moderate size, the anterior 

 larger than the posterior. Anterior area large, slightly concave dorsally, orna- 

 mented with fine radial ribs. 



Ornamentation consists of 18 to 20 main ribs with a few smaller ribs pos- 

 teriorly. The ribs are strong, with sharp summits, but become somewhat 



