TO 



LAND AND FRESH- WATER SHELLS OF N. A. [PART L 



Helix vortex, Pfr. — Shell umbilicated, depressed, pale bluish- 

 white, pearly, very thin, transparent ; whirls five, prominent, with ex- 

 ceedingly minute, oblique strice of increase ; suture deeply 

 Fig. 115. impressed ; base somewhat convex ; axis open, umbilicus 

 infundibuliform ; aperture flattened-transverse ; peristome 

 thin, acute, not reflected. Greater diam. 6, lesser 5^; 

 height 2| mill. 



Helix vortex, Pfeiffer, Arch, f, Nat. 1839, II, 351 ; Men. 

 Hel. Viv. I, 95. — Chemnitz, ed. 2, II, 110, pi. Ixxxviii, 

 f. 7-9.— Reeve, Con. Icon. 644 (1852).— Gould, Terr. 

 Moll. Ill, 34.— W. G. BiNNEY, Terr. Moll. IV, 117. 

 Eelix vortex. Helix selenina, GouLD, Bost. Proc. Ill, 38 (1848) ; in Terr. 



Moll. II, 240, pi. xxix, a, f. 2 ; pi. xlviii, f. 2.— Reeve, 

 Con. Icon. 716 (1852). 



Hi/alina vortex, Tkyon, Am. Journ. Conch. II, 252, pi. iv, f. 

 28 (1866). 



Fig. 116 



Southern Florida and the adjacent islands ; also 

 some of the West Indies. 



The species is apparently viviparous — Fig. 116 

 representing an embryonic shell taken from an adult 

 by Mr. Morse. 



Fig. 117. 



Helix iiicmstata, Poey. — Shell umbilicated, depressed, smooth, 

 horn-colored, usually incrusted with dirt, with crowded strise ; spire 

 slightly elevated, composed of four or five well-rounded 

 whirls separated by a deeply impressed suture ; beneath 

 with a broad umbilicus, one-third the diameter of the shell, 

 exhibiting all tlie whirls within ; aperture circular, being 

 but slightly impinged upon by the penult whirl, its ex- 

 tremities joined by a slightly appressed scale of enamel, 

 rendering the peristome continuous ; peristome slightly 

 reflexed, so as to render the aperture somewhat campanu- 

 late. Greater diam. 4|, lesser 4 ; height 2 mill. 



Helix incrustata, Poey, Memorias, I, 208, 212, pi. xii, f. 

 11-16.— Pfeiffer, Mon. Hel. Viv. Ill, 632.— W. G. 

 BiNWEY, Terr. Moll. IV, 68. 

 Helix saxicola, GoDLD in Terr. Moll. II, 174, pi. xxix, a, f. 4, not Pfeiffer. 

 Helix incrassala, Reeve, Con. Icon. 972. 



Pseudohiialina incrustata, Tryox, Am. Journ. Conch. II, 265, pi. iv, f. 61 

 (1866). 



