114 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
folds of growth upon the sides of the valves are also remarkably, conspicuous, rendering 
the surface rugose, and the basal sinuation is very strongly defined; in some of the more 
aberrant forms the posterior side is so much shortened that the umbones are nearly 
mesial ; they are then much elevated, and an oblique keel descends to the infero-posterior 
extremity. Our illustration faithfully represents this variety, numerous specimens of 
which have been placed at our disposal by the kindness of Mr. Walton. 
Carpium ciososum, Bean. Tab. XXXVIIL figs. 2, 2 a, 2 4. 
CarpDIUM GLOBOsUM, Bean, in Mag. of Nat. Hist., 1839, p. 60, fig. 18. 
Testa suborbiculari, equilatera, convexa, marginibus ellipticis curvatis ; superfieve striis 
concentricis, tenuissimis, crebris instructis. 
Shell suborbicular, equilateral, convex ; the umbones moderately produced, acuminated, 
and incurved ; the margins of the valves are elliptically curved; the surface has very deli- 
cate, regular, closely arranged, concentric striations. 
The length and breadth are equal; the diameter through the valves is two fifths less. 
Our illustration is taken from the original specimen figured by Mr. Bean; its outline 
should be somewhat more orbicular. The striated surface readily distinguishes it from 
Cardium cognatum, Phil., which in other respects it resembles. 
Geological Position and Locality. he Cornbrash of Scarborough ; in the collection 
of Mr. Leckenby. 
Litnopomus Porter, Lye. Tab. XL, fig. 29. 
Testa parva ovato-oblonga, convexa, angusta, umbonibus obliquis, subterminalibus ; 
margine anteriore recto, posteriore elliptico curvato, costis longitudinalibus numerosis, 
tenuibus lineis concentricis decussatis. 
Shell small, ovately oblong, narrow, convex; umbones oblique, subterminal; anterior 
border straight, its sides steep; posterior margin curved elliptically ; longitudinal costa 
numerous, delicate, closely arranged, sometimes bifurcating towards the lower border, and 
decussated by closely arranged, concentric lines. 
The ornamentation is most prominent towards the middle of the valves, and is very 
faintly traced upon the anterior side. It is allied to Lithodomus parasiticus, Desl., Mor., 
and Lye. (‘ Gr. Ool. Mon.,’ “ Biv.,” p. 41, Tab. IV, fig. 19), but has greater convexity, 
and is more narrow and cylindrical; the numerous coste and decussating lines are also 
distinctive features. 
Geological Position and Locality. Collected by W. Walton, Esq., in the Great Oolite 
of Hampton Cliffs, near Bath. 
Dedicated to Henry Porter, Esq., M.D., who has investigated the geology in the 
neighbourhood of Peterborough. 
