B. ETHERIDGE, JTJN., ON" IOWEE-CARBONIFEBOUS IKVEHTESRATA. 15 



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 appear- 

 ance to M. sublamellosa from that possessed by M. lamellosa. It 

 also bears a general resemblance to the Myalince figured by Prof. 

 W. King from the Permian rocks of England. 



Loc. and Horizon. In hardened Cyprid shale, quarry under Craig- 

 lockhart Hill, on north side of the Colinton Road near Edinburgh ; 

 Cement-stone group. 



Genus Ntjcttlana, Link, = Leda, Schumacher. 

 Nuculana Sharmani, sp. nov. PI. 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. Yentral 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 striae ; on the posterior end these striae widen out, 

 become coarser and broader, and assume the aspect of small waves 

 or fluctuations. 



Obs. Erom Leda attenuata, Eleming, the present species is distin- 

 guished by the more central position of the beaks, and much more 

 equal-sided appearance of the shell, blunter termination of the pos- 

 terior end, and smaller and narrower escutcheon. Erom Nucula 

 (or Leda ?) birostrata, M'Coy *, it is distinguished by its straighter 

 posterior end and larger antero-ventral development ; from Nucula 

 (or Leda ?) clavata, M'Coy f , by the more central position of the 

 beaks, and longer anterior end. Erom Nucula (or Leda ?) leiorliyn- 

 chus, M'Coy %, the ornamentation of the posterior end will at once 

 distinguish it. Leda intermedia, mihi, is a far more laterally com- 

 pressed 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 Palaeontologist 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 Eoss. England, 1850, p. 185. 



* Synopsis Carb. Eoss. Ireland, 1844, p. 68, pi. xi. fig. 23. 

 t Ibid. p. 69, pl.xi. fig. 25. 

 J Ibid. p. 69, pi. xi. fig. 27. 



