LIMA. 33 



Ornamentation consists of 10 to 12 strong ribs with broad interspaces. On the 

 posterior part of the shell the ribs are more widely separated and the interspaces 

 flatter than on the anterior part. In the interspaces there are small radial ribs 

 separated by broad spaces. 



Remarks. — The only specimens seen are a few imperfect internal moulds with 

 very small portions of the shell preserved. L. interlineata appears to be allied to 

 L. gaultina (see above) but is distinguished by possessing fewer ribs with broader 

 and flatter interspaces. The smaller radial ribs are perhaps also better developed 

 than in L. gaultina. 



Type. — In the Sedgwick Museum, Cambridge. 



Distribution. — Cambridge Greensand (derived from the Gault). 



Lima (Mantellum) intermedia, d'Orbigny, 1847. Plate VI, figs. 2a, b, 3, 4a — c. 



1847. Lima intermedia, A. d'Orbigny. Pal. Franc. Terr. Cret., vol. iii, p. 550, 



pi. ccccxxi, figs. 1 — 5. 

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



1869. F. J. Pictet and G. Campiche. Foss. Terr. Cret, Ste. 



Croix (Mater. Pal. Suisse, ser. 5), 

 p. 168. 

 ? 1877. A. Fritsch. Stud, im Gebiete der bohm. Kreideformat. : 



II, Weisseuberg. u. Mahiitz. Scbicht,, 

 p. 134, fig. 123. 



Description. — Shell moderately compressed, oblique, oval or rounded-oblong, 

 higher than long. Antero-dorsal border rather long and roughly parallel to the 

 slightly curving postero-ventral border; both curve gradually and regularly to 

 join the posterior border. Postero-dorsal shorter than the antero-dorsal border. 

 Umbones inconspicuous, close together. Apical angle about 100°. Ears small, of 

 nearly equal size, the posterior with three or four small radial ribs and with growth - 

 ridges. Anterior area moderately large, slightly convex except near the umbones, 

 smooth or with a few small ribs at the sides. 



Ornamentation consists of 20 to 23 ribs. Those on the antero-ventral region 

 are strong and roof-like, and, in old specimens, bear a smaller rib on each 

 side ; posterior to this region the ribs become much smaller and less elevated, 

 some being almost linear and with broad and nearly flat interspaces. At the 

 bottom of the furrows and in the middle of the flat interspaces there is a linear 

 rib. In well-preserved specimens very fine radial ribs and concentric lines 

 are seen. 



5 



