70 CARBONIFEROUS LAMELLIBRANCHIATA. 



Street (PI. XQI, fig. 9). Its posterior ear, however, is wanting. On comparing 

 this specimen with the type of M'Coy's Aviculopecten docens (PL XIII, fig. 14), 

 which is in the Jenkinson Collection of the Woodwardian Museum, there can he no 

 doubt of the identity of the two shells. M'Coy's type is also a cast of a left valve, 

 and does not exhibit the radiating ribs on the posterior ear figured by him ; but 

 he figures another specimen from the Carboniferous Limestone of Derbyshire, 

 which has some of the external characters preserved. In his account of A. docens, 

 M'Coy mentions the fact that the shell is identical with his Pecten flexuosus, but 

 owing to the preoccupation of that name it was necessary to introduce another. 

 M'Coy's description is very good and accurate. 



The specimen figured by Phillips as P. iMcatas is no doubt the testiferous 

 example of A. semicostatits. I have figured this shell (PL XIII, fig. 10), a left 

 valve, almost perfect except part of the anterior ear. I have been fortunate to 

 find a specimen showing a hinge-plate, in the collection of Mr. R. Law. It is a 

 left valve (PL XIII, fig. 11), and was obtained at Poolvash, Isle of Man. 



Aviculopecten dissimilis, Fleming, sp., 1828. Plate XIII, figs. 1—8. 



Pecten dissimilis, Fleming, 1828. Hist. Brit. Auim., p. 387. 



— — Phillips, 1836. Geo]. Yorlcs., pt. ii, p. 212, pi. vi, fig. 17. 



— aeenosus, Phillips, 1836. Ibid., p. 212, pi. vi, fig. 20. 



— ottonis, Portlock, 1843. Eep. Geol. Londonderry, p. 436, pi. xxxvi, 



fig. 10. 



— abenosus, M'Coy, 1844. Synops. Carb. Foss. Ireland, p. 89. 

 coslatus, M'Coy, 1844. Ibid., p. 90, pi. xviii, fig. 2. 



— concentrico-stiuatus, M'Coy, 1844. Ibid., p. 91, pi. xiv, fig. 5. 

 dissimilis, M'Coy, 1844. Ibid., p. 91. 



rugulosus, M'Coy, 1844. Ibid., p. 98, pi. xvii, fig. 7. 

 ? — undulatus, M'Coy, 1844. Ibid., p. 101, pi. xvii, fig. 12. 



— subfimbriatus, de Vemeuil, 1845. Geol. Eussie de l'Europe, p. 327, 



pi. xxi, figs. 5 a, b. 

 arenosus, Brown, 1849. Illust. Foss. Conch., p. 156, pi. lxv, fig. 10. 

 Aviculopecten ccelatus, M'Coy, 1855. Brit. Pal. Foss., p. 483, pi. 3 e, fig. 5. 



— B. Etheridge, jun., 1876. Ann. Mag. Nat. Hist., ser. 4, 



vol. xviii, p. 97. 



— de Koninck, 1885. Ann. Mus. Eoy. d'Hist. Nat. Belg., 



torn, xi, p. 225, pi. xxxviii, figs. 5 — 8. 

 textilis, de Koninck, 1885. Ibid., \>. 225, pi. xxxiv, fig. 30. 



Specific Characters. Shell of medium size, suborbicular, with large ears. The 

 righ.1 valve gently convex, the left more so. The margin subcircular. The 



