LIMA. 35 



Non 1836. LIMA ELONGATA, A. Goldfms. Petref. Germ., vol. ii, p. 87, pi. cii, fig. 13 



(L. Miinsteriana, d'Orbigny). 

 F. A. Homer. Verstein. nord-deutsch. Oolith.-geb., p. 79, 



pi. xiii, fig. 11 (L. longa, Eomer, 1841). 



? 1841. F. A. Eomer. Die Verstein. d. nord-deutsch. Kreidegeb., 



p. 56. 



- 1845. E. Forbes. Quart. Journ. Geol. Soc., vol. i, p. 248 (L. 



parallela, Sowerby). 



? - 1846. A. E. Beuss. Die Verstein. der bohm. Kreideformat., pt. 2, 



p. 33, pi. xxxviii, fig. 6, non 9 ( = L. Reussi, 

 d'Orb.). 



- 1863. A. v. StrombecJc. Zeitschr. d. deutsch. geol. Gesellsch., 



vol. xv, p. 104 (L. Schmeisseri, 

 Wollemann). 



?-- 1872. H. B. Geinitz. Das Elbthalgeb. in Sachsen (Palseonto- 



graphica, vol. xx, pt. 2), p. 40, pi. ix, 

 figs. 9, 10. 



? 1877. A. Fritsch. Stud, im G-ebiete der bohm. Kreideformat. : 



II, Weissenberg. u. Malnitz. Schicht., p. 132, 

 fig. 116. 



Description. Shell of moderate convexity, subquadrangular or nearly oblong, 

 rounded anteriorly, much longer than high. Antero-dorsal margin long, nearly 

 straight, and nearly parallel with the postero-ventral margin; postero-dorsal 

 margin short, nearly straight. Apical angle about 100. Umbones sharp, close 

 together. Ears of moderate size. Anterior area large, the dorsal part slightly 

 concave, ornamented with from five to seven fairly strong ribs which are crossed 

 by fine growth-ridges. 



Ornamentation consists of 19 or 20 very strong ribs, with sharp, and some- 

 times (especially on the dorsal part of the shell) slightly serrate summits. The 

 ribs have usually at their summits a distinct ridge with a shallow furrow on each 

 side, which sometimes gives rise to the appearance of a ridge on each side of the 

 rib. The grooves between the main ribs are deep, rounded, distinctly limited, and 

 of about the same width as the ribs. On the'dorsal portions of the shell fine radial 

 ribs occur on both ribs and grooves ; on the ventral portions they are not seen. 

 Fine concentric growth-lines cross both ribs and grooves, and some few (at 

 intervals) are more. distinct. 



Measurements : 



Length 

 Height 



(1. 3, 5, 6) Chalk Marl, Folkestone. 



(2) H. subglobosus zone, Stoke Ferry. 

 (4) Chalk Marl, Ventnor. 



