the Oral Folds in the Shells o/Clausilia. 211 



the following: — a. G aumenf alten, plicce palatales ; b. Colu- 

 mellarfalte, plica columellaris ; [c] Die mondformige Falte, 

 plica lunata. 



In 1841 Cantraine* sought to establish the terms which 

 appear under his name in the table. Some of these are still 

 employed by the French school of conchologists. 



Fortunat Forster, in 1842 f, proposed a series of names 

 which, inasmuch as they were somewhat fanciful and intro- 

 duced no new or useful point, may here be passed by. 



The systems of Rossmassler and Cantraine were correlated 

 in 1848 by PfeifferJ, who subdivided the plicce palatales into 

 (a) superai, and (b) inferce. 



Up to this period only those folds visible within the mouth, 

 or whose existence could be traced through the semitrans- 

 parent shell, had attracted attention ; but in 1850 A. Schmidt§ 

 first described the lamella spiralis and employed it for the 

 purpose of classification. 



Dupuy (1850)|| followed Rossmassler and Pfeiffer, but added 

 to the list a Callus palatalis (PI. XI. A, fig. 4, c.p.). This, 

 however, judging from the example quoted — Clausilia phale- 

 rata } Ziegl.= C. fimbria ta, Muhlf. — is merely a thickening of 

 the shell-wall in a narrow tract running nearly parallel to the 

 lines of growth, and consequently at right angles to the true 

 folds. He also gave an explanatory figure of such folds 

 as are visible within the aperture. 



In 1853 Caillaud^j discussed the lamellae and gave a good 

 dissected figure showing their arrangement in the interior of 

 the shell, but he omitted all reference to the plica? ; and, 

 although he correctly figured the lamella inserta, made no 

 allusion to it. 



JMoquin-Tandon (1855)** merely followed Dupuy in every 

 particular. 



The terminology at present in use was practically perfected 

 by A. Schmidt in 1868ft, when he introduced the terms 

 lamella parallela } lamella fulcra its, and lamella inserta. 



* " Malacol. Medit. et littorale,'' Nouv. Mem. Acad. Roy. Bruxelles, 

 xiii. no. 7, pp. 144, 145. 



t Nova Acta Acad. Caes.-Leop. Carol. Nat. Cur. xix. pt. ii. pp. 251- 

 282 (oue plate). 



J Monog. Helic. Vivent. ii p. 395. 



§ Zeitsch. f. Malakozool. 1850 (1851), p. 186. 



|| Hist. nat. Moll. France, pp. oo9, 340 (note). 



*] Joura. Conch, iv. pp. 410-424, pi. xiii. tig. 4. 



** Hist. hat. Moll. terr. et rluv. France, torn. ii. p. 310. 



tt ' System europaisch. Clausilien,' pp. 0-8. 



