PROM THE INFERIOR OOLITE. 505 



the greater indistinctness of its markings. As Goldfuss, Thurinan 

 and Etallon, and Chapuis and Dewalque all give the same characters 

 for the latter shell, I have thought it better to distinguish the present 

 one, although at first inclined to agree with others in supposing it to 

 belong to L. aciculata. The individuals do not seem to vary much, 

 but preserve their common characteristics. It approaches L. ovalis, 

 Sow., but is flatter and less transverse, besides having more defined 

 ears than that shell. It also very much resembles Lima pseudovalis, 

 Waagen, in Benecke's geogn.-pal. Beitr. vol. i. t. 30. fig. 3, but is 

 distinguishable by the presence of well-defined ears, by being flatter 

 and anteriorly broader, by having more distant and less incurved 

 umbones, and by not having narrow and elevated ribs. 



Lima contorquexs, n. sp. Plate XVII. figs. 3, 3a, 3h. 



Shell moderately convex, flattened near hind margin ; valves 

 meeting at a moderate angle. Umbo very posterior, facing an- 

 teriorly, pointed and incurved. Lima-line rather indistinct, con- 

 cave anteriorly, about three fourths of the length of the shell in that 

 direction. Lunule very deep and concave. Posterior wing narrow, 

 ill-defined, rendered rugose by crowded growth-lines. Greatest con- 

 cavity about one third behind the lima-line. Inferior margin nearly 

 semicircular. Ribs about 60, undulating, flattened, depressed, divided 

 only by shallow, but very distinct, undulating, linear, punctate 

 channels. Ribs often having a second indistinct channel on their 

 flat tops, so as to be somewhat dichotomous. Growth-lines distant, 

 regular, small and white. 



One specimen in the Sharp Collection in the British Museum. 



Dimensions. 16 lines long, by 13 wide, and 6 deep (for both 

 valves). 



This shell has much less obliquity than most Limce of the Inferior 

 Oolite. It is very similar to Lima comatida, Buv. Meuse, t. 18. 

 figs. 20-25, but has a sharper beak, and more distinct posterior 

 ear ; its posterior side is much less dilate, its lunule longer, and its 

 rays fewer. Lima semilunaris, Goldf. Petr. Germ. 1. 102. fig. 2, is a 

 much more contorted shell, without a distinct lunule, and rayed 

 only on the sides. 



Lima cebleerexs, n. sp. 



Shell elongate, ovoid, slightly oblique, and very flat. Umbo 

 acute, proximate, subcentral. No lima-line or lunule. Wings 

 large, equal, and triangular. Anterior wing covered by rugose 

 growth-lines. Margin slightly concave below anterior wing, con- 

 vex in the antero-inferior region, and then proceeding in a low 

 curve to the posterior part, where it becomes strongly convex before 

 reaching the other wing. Ornamentation consisting of about forty 

 very distant threads or ridges, crossed by very numerous, foliaceous, 

 concentric ridges, which were evidently freely lamellar towards 

 the margins. 



Dimensions. 33 lines long, by 25 wide, and 12 deep. 



There are three specimens in the British Museum, one from the 



2o2 



