LINGULA. 



Genus — Lingula, Bruguiere. 1789. 



Shell inequivalved, one valve more convex than the other, more or less oval, elongated, 

 tapering, and pointed at the beaks, widened at its palleal region, without hinge, valves 

 held together by the adductor muscles; attached to submarine bodies by a long muscular 

 peduncle issuing from between the beaks, a groove existing for its passage in that of the 

 larger valve, without any shelly support ; structure horny, covered by an epidermis ; two 

 muscular impressions on the one, four on the other valve. 1 



Obs. We are not acquainted with any recent British Lingula. Two species are found 

 in the Tertiary strata. 



1. Lingula Dumontieri, Nyst. Plate I, figs. 10, 10 a h , 11. 



Lingula Dumontieri, Nyst. Coq. et Poly. Test, de la Belgique, p. 337, pi. xxxiv, 



fig. 4 a " °, 1843. 



— mytiloides, Nyst. 1835. Rech. sur les Coq. Fos. d'Anrers, p. 21, pi. iv, 



fig. 80 (non Sow.) 



— fusca, S. Wood. Mag. of Nat. Hist., p. 253, 1840, (not figured or described.) 



— — Morris. Cat. of Brit. Fossils, p. 122, 1843. 



— — Bronn. Index Pal., p. 655, 1848. 



— — Tennant. A Stratigraphical List of British Fos., p. 17, 1847. 



Diagnosis. Shell almost inequivalve, of a lengthened oblong form, valves convex, 

 slightly compressed, and rounded anteriorly ; beak acute, not much produced ; shell 

 thin, and brittle ; surface smooth, shining, of a ferruginous brown colour, and marked by 

 numerous concentric lines of growth. Muscular impressions strongly marked in the 

 interior of both valves, arranged in pairs, as in all Lingulas. Length 12 ; width 5 lines. 



Obs. This species seems to have been first noticed in the Crag of Antwerp by M. Nyst, 

 under the erroneous name of L. mytiloides, Sow., which error was afterwards acknowledged 

 by the same author in another work. In England, it was first discovered in the Coralline 

 Crag of Sutton by Mr. S. Wood, who published it under the appellation of L. fusca, 

 unfortunately without figure or description, in the 'Annals of Nat. Hist.,' 1840; later in 

 1843 it was described and figured by M. Nyst, under the name of L. Dumontieri, which 

 denomination we feel bound to accept in preference to that of Mr. S. Wood, as a species 

 published without description or figure cannot claim priority. M. Nyst mentions it as 

 abounding in the Crag of Antwerp, where it has not, however, been found perfect, the 

 anterior portion being always broken, and this is generally the case with most of our English 

 specimens, no doubt owing to the extreme thinness of its shell. L. Dumontieri somewhat 

 approaches in form to Lingula Hians (Swains), from Port Essington, but it is perhaps 

 smaller and more acute posteriorly. However, it is difficult to distinguish the different 



1 For more ample details, see General Introduction. 



