FAMILY ZONITID^ 35 



and I do not believe it occurs on the treeless grassy slopes of the 

 peninsula. I suspect that the wide-stretching glacial area to the 

 north and west of Yakutat Bay, puts an impassable barrier to its north- 

 western migration, and that it may not exist in the forests beyond that 

 area. 



This is the largest shell -bearing Pulmonate known to live in Alaska, 

 but is surpassed by the great slug Ariolimax^ which often extends to 

 the length while preserv ing the diameter of a large cigar. 



Circinaria variety sportella Gould. 



Helix sportella Gould, Proc. Boston Soc. Nat. Hist, ii, p. 167, 1846; Moll. 

 U. S. Expl. Exp., p. 37, fig. 42, 1852. 



This is a variety of C vancouverensis of smaller size, and intensified 

 sculpture, both spiral and incremental. Intermediate forms, to which 

 several names have been applied, connect it with the typical form. It 

 accompanies the latter throughout its range, but occurs in some locali- 

 ties which do not support the larger form. Among northern localities 

 it has been collected at Saanich, Comox ! Union Bay ! Salt Springs 

 Island and Chilliwak Lake, British Columbia ; at Annette Island ! (with 

 variety hybrida Ancey) and Lituya Bay ! Alaska. 



Circinaria variety hybrida Ancey, 1888. 



This form is reported from Vernon and Comox, British Columbia, 

 and Annette Island, Alaska. 



Circinaria hemphilli Binney and C. voyana Newcomb, have not 

 been authentically reported north of the boundary, though it is said 

 both of them have been collected in the Puget Sound region. 



Family ZONITID^. 

 Genus Vitrina Draparnaud. 



Vitrina Draparnaud, Tabl. Moll. Terr. France, pp. 33, 98, 1801 ; Hist., Nat. 



Moll. Terr. France, pp. 23, 30, 119, 1805. Type Helix pellucida Miiller, 



Venn. Terr., p. 215. 

 Vitrinus Montfort, Conch. Syst., 11, p. 238, 18 10. 

 Cobresia Jac. Hubner, Mon. Test. Bairische Landschn. Cobresien, 1810 ; 



(pages and plates not numbered). 

 Hyalina Studer, Syst. Verz. Schweiz. Conch., p. 11, 1820: not of Schu- 

 macher, 1817. 

 Umacina Hartmann, Neue Alpina, i, p. 206, 1821 ; Sturm's Deutschl. Fauna, 



abth. VI, heft v, pp. 41, 54, 1821 ; not of Cuvier, 1817. 

 Helicolimax F^russac pere, Mem. Soc. Med. d'Emul., iv, p. 390, 1802 ; et 



fils, Tabl. Syst. des Lim., pp. 19, 21, 1821, 

 Semilimax Ferussac pere, Der Naturforscher (Halle), pt. 28, 1802, fide Fer- 



russac fils, loc. cit., 1821. 



