TALLOXIA. 225 



196. Vallonia costata, Mailer. 



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



Rossmjissler, Iconofjr. ii, 1888, tig:. 4o9 ; Chenu, Man. Conchyl. 



i, part 2, 1860, p. 4o2, tig. 3868. 

 Helii- (A'lnjjlexis) crenelles, ]h'o\\n, 111. Conch. 1821, pi. 41, figs. 78, 



79. 

 Helix {Amplextts) erenella, ibid., ed. 2,' 1844, p. 45, pi. 14, fi<?s. 78, 



79. 

 Heliv {Gluphyrn) costata, Albers, Die lleliceen, 1850, p. 87. 

 Helix ( Vallonia) puJcheUa, var. costata, von Marten.s, Die lleliceen, 



ed. 2, 1800, p. 101 ; Nevill, Hand List, i, 1878, p. 75. 

 Vallonia costata, Theobald, .1. A. 8. B. xlvii, 187b, p. 144 ; Sterlci, 



Proc. Ac;id. Nat. Sci. Philadelphia, 189.8, p. 259, pi. 8, tig. C 



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



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



Oritjinal description : — " Helix testa subdepressa, umbilicata, 

 cinerea ; spiris costatis ; apertura circulari ; labro albo reflexo. 



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

 Anfracius quatuor externa costati, sive plicis transversis armati ; 

 in niajori anf ractii triginta mimeravi ; hie subtus glaber est. 

 Apertura circularis ; vix duodecima peripherige pars ab anfractu 

 o])i)Osito interseeatur, cum in antecedente fere quarta. Costa?, si 

 testa lutnini obvertatur, in sola apertura transparent. Labrtmi 

 album, planum, reflexum.'' (Miiller.) 



" Moderately uinbilicated, more widely so for the last half 

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

 reddish horn colored, with rather regularly set memhranous ribs 

 and finer striie bet\^een them ; nucleus with tine revolving lines. 

 AVhorls 3.7, slightly flattened above and below the periphery, at 

 the circumference soir.e\Aliat angular, with a dee/) suture, rather 

 rapidly increasing ; the last whorl expanding to the aperture 

 shortly and modeiately descendiiu/ 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 strowjhj and abruptly everted, with a stronr/ white lip." 



Greater diain. 25, 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. Kadula with (59-72 transverse rows of 

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

 paratively small, especially the ectodonts. On the marginals the 

 (3-7 cusps stand immediately on the plate, not on a common 

 base. 



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

 pidchella ; but it is sufliciently 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 



