NUCULANA ATTENUATA. 195 



One of the three specimens described by Sowerby as Nucula in the Appendix to 

 Prestwich's ' Geology of Coalbrookdale ' as N. acuta should more correctly be 

 referred to Nuculana ; the Nucula accipiens, an elongate shell, is the young of 

 that author's Unio Urii. 



Koenen's Area Ritterhauseni is, I think, identical with Nucula Isevistriata, Meek 

 and Worthen ; but the figures make it perfectly plain that the shell belongs to 

 Nuculana. 



As a rule, the genus is found only in beds of shale in British localities. I have 

 specimens, however, from Pittenween, Fife, which were in a limestone matrix. 



Nuculana attenuata, Fleming, sp., 1825. Plate XV, figs. 1 — 16. 



Multiarticulate cockle, Ure, 1793. Nat. Hist, of Eutherglen, p. 310, pi. xv, fig. 5. 

 Non Nucula clavifoemis, Sowerby, 1824. Mineral Conchology, vol. v, p. 119, pi. 



cceelxxvi, fig. 2. 



— attenuata, Fleming, 1828. Hist. Brit. Animals, p. 403. 



— clavifobmis ?, Phillips, 1836. Geol. Yorkshire, p. 210, pi. v, fig. 17. 



— attenuata, Morris, 1843. Catal. Brit. Foss., p. 94. 



— — M'Coy, 1844. Synops. Carbonif. Foss. Ireland, p. 68. 

 ? bibosteata, M'Coy, 1844. Ibid., p. 68, pi. xi, fig. 23. 



- — clavata, M'Coy, 1844. Ibid., pi. xi, fig. 25 (figure, not description). 

 longieostbis, M'Coy, 1844. Ibid., p. 70 (description, not figure). 

 ? — leioehynchus, M'Coy, 1844. Ibid., p. 69, pi. xi, fig. 27. 



— clavifobmis, Brown, 1849. Illustr. Foss. Conch., p. 185, pi. Ixxvi, 



fig. 38. 

 Leda clatifoemis, d'Orbigny, 1850. Prodrome paleont., p. 129. 



— bibosteata, d'Orbigny, 1850. Ibid., p. 129. 



— clavata, d'Orbigny, 1850. Ibid., p. 129. 



? — leiobhyncha, d'Orbigny, 1850. Ibid., p. 129. 

 Nucula ? attenuata, M'Coy, 1855. Brit. Palaeoz. Foss., p. 511. 

 Leda attenuata, Baily, 1862. Mem. Geol. Surv. Ireland, Expl. Sheet 127) p. 9, 



figs. 2 a — c. 

 Non Nuculana bellisteiata, var. attenuata, Meek, 1872. U.S. Geol. Surv., Final 



Report Nebraska, p. 206, pi. x, 

 figs. 11 a, b. 

 Ctenodonta attenuata, Bigsby, 1878. Thesaur. Devonico-Carb., p. 303. 

 Leda attenuata, Romer, 1876. Lethaea Palaeoz., Atlas, pi. xliv, figs. 11 a, b. 

 Nuculana attenuata, Etheridge, 1885. Brit. Fossils, pt. 1, Palaeoz., p. 288. 



Specific Characters. — Shell moderately gibbose, produced and attenuated 

 posteriorly almost to a point. The anterior end is of moderate size, and has a 

 regularly rounded margin. The inferior or ventral border is gently convex for 



