402 helicidj:. 



Ilyalina ferrea, Trton, Am. Journ. Conch, ii. 2.5.3, pi. 4, fig. 32 (1866). 

 Helix feirea, Morse, Amer. Nat. i. .544, fig. .37 (1867), 



Shell umbilicated, depressed-globose, transparent, of a very light 



steel gray color, not shining, marked with very del- 

 rig- 663. . ? '' 1 • T , 



icate incremental wrmkles and microscopic revolv- 

 ing lines ; spire slightly elevated ; whorls three, 

 rounded, the last rapidly enlarging, globose ; aper- 

 ture large, transversely sub-circular ; peristome sim- 

 ple, acute, its extremities not approaching, that of the columella 

 scarcely sub-reflected. Greatest diameter two and a half, height 

 one and one fourth millimetres. 

 Maine. 



Hyalina chersina. 



Fig. 105. 



Shell minute globose-conic, pellucid, very smooth and shining; whorls six, sut- 

 ure deep ; aperture narrow ; lip simple ; umbilicus closed. 



Helix chersina, Say, Journ. Phila. Acad. ii. 1.56 (1821) ; Binney's ed. 18, 81. — Binney, 



Bost. Journ. Nat. Hist. iii. 416, pi. 26, fig. 3 (1840) ; Terr. Moll. ii. 243, pi. 17, fig. 



4. — GouLD,Inv. Isted. 185, fig. 105 (1841). — Adams, Vermont Moll. 162 (1842); 



Sillim. Journ. [1] xl. 273. — De Kay, N. Y. Moll. 44. pi. 35, fig. 338 (1843). — W. 



G. Binney, Terr. Moll. iv. 119. — Morse, Amer. Nat. i. 544, fig. 38 (1867). 

 Helix egenn. Say, Journ. Phila. Acad. v. 120 (1825) ; Binney's ed. 30. — De Kay, N. 



y. Moll. 45 (1843). — Chemnitz, 2d ed. i. 237, pi. 25, figs. 19-21 ? (1846).— 



Reeve, Con. Icon. No. 1263 (1854). — Pfeiffer, Mon. Hel. Viv. i. 31 ; not of 



Gould in Terr. Moll. 

 Helix fulca, Draparnand teste Mighels (Bost. Journ. iv. 333) ; Chemnitz ; Pfeiffer, 



Mon. i. 30; Reeve, Forbes and Hanley. 

 Comilus chersinus, Morse, Journ. Portl. Soc. i. 19, figs. 44-46; pi. 2, fig. 4 ; pi. 7, fig. 



45 (1854). 

 Conulus chersina, Tryon, Am. Journ. Conch, ii. 256, pi. 4, fig. 37 (1866). 



Shell minute, sub-globose-conic, thin, pellucid, very smooth and 



shining, of a smoky horn color ; whorls separated by a deep suture, 



and so crowded that they appear much higher than 



Fig. 664. broad, and present an elevated, somewhat turreted 



spire, with a rounded apex ; they are so smooth that 



scarcely any traces of the lines of growth are visible ; 



aperture semi-lunar, narrow, much higher than broad, 



H. chersina. ^^ about au cqual width above and below ; lip simple ; 



base convex, uml)ilical region indented, but closed. 



Diameter about one tenth of an inch ; height somewhat less. 



Found abundantly about the margin of Fresh Pond, under frag- 

 ments of wood, in company with Succinea ovalis, Pupa modesta, 



