506 REV. G. E. WRLDBORNE ON SOME FOSSILS 



" Marly bed, Down Cliff, Dorset," and two from the Limestone and 

 Upper beds of Duston. 



It belongs to the same group as L. rigidida, Phill. (non Morris and 

 Lycett ?), and L. antiquata, Sow. Sowerby's shell differs from it in 

 the character of its radiations, which are close and rounded, as seen 

 in his figured specimen from the middle Lias in the Bristol Museum. 

 L. antiquata, Miinst., Goldf. t. 102. fig. 14, seems to be distinct from 

 this, and more nearly approaches the present form, but is unlike it in 

 its convexity, its smaller ears, its inconsecutive rays, and its distant, 

 prominent, concentric ridges. L. rigidula, Phill. (not Morris and 

 Lycett), though possibly the same as Miinster's species, appears from 

 the figure (Geol. Yorksh. vol. i. t. 7. fig. 13) to be much more curved 

 and convex than the present species, with stronger and closer ribs, 

 and a much longer anterior ear. Lima succincta, Schl., is given by 

 Giebel as a synonym of Lima Eermanni, which is very dissimilar 

 both in contour and in decoration. 



Lima edttcta, n. sp. Plate XVII. figs. 4, 4a. 



Shell small, oblique, moderately convex, very transverse. Umbo 

 acute, prominent but attenuated, very distant, and very posterior. 

 Wings small, narrow, nearly equal, and marked by the lines of 

 growth. Lima-line depressed, nearly the length of the shell in 

 that direction. Lunule smooth and concave. Greatest depth at the 

 point one third from the lima-line and one third from the umbo. In- 

 ferior margin moderately convex ; the curve deepening very much 

 round the infero-posterior, and still more round the infero- anterior 

 portions. The apical part of the surface smooth, the rest covered 

 with very fine elevated and undulating ribs with flattened tops, 

 which are divided by narrower smooth grooves and broken by 

 occasional well-defined growth-lines which cause them to change 

 their direction. 



Dimensions. Length 13 lines, breadth 9. lines. 



There is a specimen of this shell in Jermyn Street, from the 

 ParJcinsoni-zone of Leckhampton, and another in the British Museum, 

 from Dundry ; and I have one from the ffumphriesianus-zoiie of 

 Cleeve Cloud. 



This shell is quite different from L. ovalis, as figured by Goldf uss 

 and by Morris and Lycett, and from the Minchinhampton and Inferior- 

 Oolite form which they represent. The two original specimens, 

 however, in the Sowerby Collection in the British Museum seem 

 different, and one of them very nearly approaches the presenc 

 species, though differing from it in the size of the puncta- 

 tions, while the other is clearly distinct both in its contour and 

 ornamentation. Our shell is totally unlike Lima rigidula, Phill., 

 Geol. Yorksh. vol. i. t. 7. fig. 13, which is a different species from that 

 figured by Morris and Lycett under that name. The latter much 

 more nearly approaches the present shell, but a comparison of the 

 two fossils, both of which are at Jermyn Street, points to their 

 being distinct. The former is more swollen posteriorly, its anterior 

 ear is much smaller, its rays are separated by much wider grooves, 



