14 CARBONIFEROUS LAMELLIBRANCHIATA. 



Obi^ercafioiis. — Speaking of L. hirnndo, cle Koninck states, " This species lias tlie 

 ventral border less arched than L. lunulata ; it is not so high, and the posterior 

 wing is more elongate." To these differences I wonld add that the line of 

 separation of the wing and convex portion of the valve is straight and not arched, 

 and the compression is more gradual, and does not extend so far backwards. The 

 rostrum is much longer and stronger, and the anterior end comparatively longer 

 and more pointed. The whole A^alve is more regularly triangular and less lunate. 



On the other hand, the valve is less triangular, less compressed, and has a better 

 marked-off and developed posterior wing than L. Thomjisoiii. 



The species does not seem to be common, and at present I have only met with 

 it at Castleton and Hill Bolton. De Koninck states that the species is very rare, 

 and comes from the Carboniferous Limestone of A'^ise. 



Leiopteeia laminosa, FItillijis, sp., 18o(3. Plate III, figs. 4—9; Plate IV, fig. G. 



Geevxllia laminosa, PJdllips, 1886. Geol. Yorks., pt. ii, p. 212, pi. vi, fig. 10. 



— Morris, 1843. Cat. Brit. Foss., 1st edit., p. 108. 



AvicuLA LAMINOSA, M'Coy, 1844. Synops. Carb. Foss. Ireland, p. 84. 

 Gervillia laminosa, Broun, 1848. Nomencl. Palaeoutol., p. 529. 



— — Brown, 1849. Illust. Foss. Conch., p. 165, pi. Ixrii, fig. 10. 

 Avicula laminosa, d'Orbifpii/, 1850. Prodrome Pak'ont., vol. i, p. 137. 



— — Morri.^, 1854. Cat. Brit. Foss., 2nd edit., p. 162. 

 Geevillia laminosa, B. Griffith, 1862. J. Geol. Soc. Dublin, vol. ix, p 93. 



Non — — W<frdle, 1863. Sleigh's Ancient Hist. Leek, pi. iii, fig. 4. 



Avicula laminosa, Bujsby, 1877. Thesaurus Devonico-Carboniferus, p. 287. 

 Leiopteeia laminosa, de KunincJ,-, 1885. Ann. Mus. Roy. d'Hist. Nat. Belg., 



torn, xi, p. 190, pi. XXX, fig. 6. 



— eostrata, de Kotiincl-, 1885. Ibid., j). 192, pi. xxx, fig. 14. 

 Aa'icula laminosa, Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoic, p. 270. 



— (Leiopteeia) laminosa, Tornqnist, 1896. FossiLfiihr. Untercarbou. 



Siidvogeseu, Abh. geol. Specialkarte Elsass.- 

 Lothr., Band v, Heft 5, p. 15, pi. xvii, 

 figs. 5, 6. 



Specific Gharaefers. — Shell of only medium size, obliquely gibbose, verv inequi- 

 lateral, irregularly subquadrate. The anterior end is very short, compressed, 

 almost triangular in shape, blunt. The anterior border descends downwards and 

 backwards ; the inferior border is roundly curved, and the posterior concave. The 

 hinge-line is straight, its upper border prolonged back^vards and rolled, forming 

 an elongated narrow process. The umbones are obtuse, hardly raised above the 

 hinge-line, and placed far forwards, not terminal. The body of the shell is 

 triangularly and obliquely gibbose, the gibbosity rising gradually both in front and 



