the shell under consideration may be known by the slightly sigmoidal outline of its anterior end, and its less-depressed hinge-line—characters which, when taken together, give a different appearance to M. sublamellosa from that possessed by M. lamellosa. It also bears a general resemblance to the Myalinæ figured by Prof. W. King from the Permian rocks of England.
Loc. and Horizon. In hardened Cyprid shale, quarry under Craiglockhart Hill, on north side of the Colinton Road near Edinburgh; Cement-stone group.
Genus Nuculana, Link, = Leda, Schumacher.
Nuculana Sharmani, sp. nov. Pl. II. fig. 18.
Sp. char. Transversely elongated, slightly clavate, moderately convex. Anterior end rounded; posterior end produced, gradually compressed laterally to the bluntly rounded point. Ventral margin convex, sloping upwards posteriorly. Unibones nearly but not quite central, a little anterior; lunule probably small and ill-defined; escutcheon or posterior lunette narrow, and not deeply marked, or bounded by ridges from the beak. Surface of the valves ornamented with imbricating striæ; on the posterior end these striæ widen out, become coarser and broader, and assume the aspect of small waves or fluctuations.
Obs. From Leda attenuata, Eleming, the present species is distinguished by the more central position of the beaks, and much more equal-sided appearance of the shell, blunter termination of the posterior end, and smaller and narrower escutcheon. From Nucula (or Leda?) birostrata, M'Coy[1], it is distinguished by its straighter posterior end and larger antero-ventral development; from Nucula (or Leda?) clavata, M'Coy[2], by the more central position of the beaks, and longer anterior end. From Nucula (or Leda?) leiorhynchus, M'Coy[3], the ornamentation of the posterior end will at once distinguish it. Leda intermedia, mihi, is a far more laterally compressed shell; and the posterior end is less attenuated than in N. Sharmani. The arched and very clavate form of L. Traquairii, mihi, may be taken as a distinctive character between it and the present species. I name the species with much pleasure after my friend Mr. G. Sharman, Assistant Palæontologist to the Geological Survey.
Loc. and Horizon. In shale with marine fossils, at Woodhall, as before.
Genus Schizodus, King.
Schizodus, King, 1844, Ann. & Mag. Nat. Hist. xiv. p. 313; Permian Foss. England, 1850, p. 185.
