VALLOSTA. 225 



196. Vallonia costata, Milller. 



Helix costata, Miiller, Verm. Terr. Fluv. Hist, ii, 1774, p. 30 ; 



Kossrnassler, Iconogr. ii, 1838, fig. 439 ; Chenu, Man. Conchy 1. 



i, part 2, 1860, p. 452, fig. 3368. 

 Helix (Amplexis] crenellus, Brown, 111. Conch. 1821, pi. 41, figs. 78, 



79. 

 Helix- (Amplexus) crenella, ibid., ed. 2, 1844, p. 45, pi. 14, figs. 78, 



79. 



Helix ( Glaphyra) costata, Albers, Die Heliceen, 1850, p. 87. 

 Helix ( Vallonia) pulchella, var. costata, von Martens, Die Heliceen, 



ed. 2, 1860, p. 101 ; Nevill, Hand List, i, 1878, p. 75. 

 Vallonia costata, Theobald, J. A. S. B. xlvii, 1878, p. 144 ; Sterki, 



Proc. Acad. Nat. Sci. Philadelphia, 1893, p. 259, pi. 8, fig. 



(radula), N (jaw) ; ibid., Man. Conch, ser. 2, viii, 1893, p. 252, 



pi. 32, figs. 18-22, 27, pi. 33, fig. 54. 



Original description : " Helix testa subdepressa, umbilicata, 

 cinerea ; spiris costatis ; apertura circular! ; labro albo reflexo. 



" Testa convexiuscula, opaca, supra fuscescens, subtus pallida. 

 Anfractus quatuor externe costati, sive plicis transversis armati ; 

 in majori anfractu triginta numeravi; hie subtus glaber est. 

 Apertura circularis ; vix duodecima peripherisB pars ab anfractu 

 opposite intersecatur, cum in antecedente fere quarta. Costse, si 

 testa lumiiii obvertatur, in sola apertura transparent. Labrum 

 album, planum,reflexum." (Miiller.) 



*' Moderately umbilicated, more widely so for the last half 

 whorl, depressed convex above, or nearly flat ; greyish to light or 

 reddish horn colored, with rather regularly set membranous ribs 

 and finer striae between them ; nucleus with fine revolving lines. 

 Whorls 3 j, slightly flattened above and below the periphery, at 

 the circumference somewhat angular, with a deep suture, rather 

 rapidly increasing ; the last whorl expanding to the aperture 

 shortly and moderately descending in front, more so at the suture 

 than on the back. Aperture rather oblique and inclined, almost 

 circular, a little flattened above, ends of margin much approximat- 

 ing, slightly protracted and auricled, connected by a thin callus ; 

 peristome strongly and abruptly everted, with a strong white lip." 



Greater diam. 2-5, lesser 2-1, alt. 1*1 mm. 



Hab. Circumboreal Europe ; Northern and Eastern Asia, as 

 far south as Kashmir ; Northern Africa ; greater part of North 

 America. 



" Jaw rather curved. Eadula with 69-72 transverse rows of 

 27 or 29 teeth ; 5 perfect laterals, on which the cusps are com- 

 paratively small, especially the ectodonts. On the marginals the 

 6-7 cusps stand immediately on the plate, not on a common 



" V. costata has, by most authors, been regarded as a variety of 

 pulcliella ; but it is sufficiently different to be distinguished at first 

 sight ; the less elevated spire, with the deeper suture, the whorls 

 not so well rounded, the last descending in front, the more oblique 

 and more circular aperture with approximate margins, characterize 



Q 



