160 



NATURAL HISTORY OF VERMONT. 



Part 1. 



FRESH WATER AND LAND SHELLS. 



preceding ; aperture nnarly orbicular, di- 

 lated ; labrurn much thickened, white, 

 reflected, scarcely interrupted by the in- 

 trusion of the penultimate whorl ; umbil- 

 icus large. Greatest breadth 0.095 inch ; 

 least breadth 0.078 inch ; height 0.05 

 inch ; divergence 160°. 



Remarks. — This species is remarkable 

 for its wide geogiaphical distribution. It 

 is common in Great Britain and a large 

 part of Europe, and in this country is 

 found as far south as South Carolina, as 

 far west as Council Bluffs, and as far 

 east as Maine. It is very abundant in 

 Bome parts of Vermont. It is the H. nii- 

 nuta of Say . 



Helix Stniii. — BiSNEV. 



Description. -Shell depressed globose, 

 with numerous fine oblique incremental 

 striae ; epidermis verj' light brown, shi- 

 ning; whorls five and a half, convex, 

 with a well impressed suture ; labrum 

 white, narrow, reflected, with a small 

 rounded tooth on the inner edge below ; 

 inner lip with a small oblique tooth on the 

 middle ; umbilicus not verj' wide but deep 

 and exhibiting all the volutions. Great- 

 est breadth 1 inch ; least breadth 0.8 inch ; 

 height 0.55 inch ; divergence 135°. 



Remarks. — This species was originally 

 described by Say with the name of//, did- 

 (lonfa, but as this name had been preoccu- 

 pied, Dr. Binney proposed that of H. 

 Saiiii. The species is rare in Vermont. 

 It is easily recognized by its narrow lip 

 and two small teeth, of which, however, 

 the one on the inner margin is some- 

 times wanting. 



Helix tridcntnla. — Say. 



Description. — :Shell depressed, a little 

 convex above, with crowded oblique in- 

 cremental stria? ; ei)idermis brown ; whorls 

 five, a little flattened above, with a dis- 

 tinct suture ; aperture three-lobed, con- 

 tracted by a groove behind tlie labrum, 

 which is white, reflected, flattened, fur- 

 nished with two acute prominent teetli ; 

 inner lip with a prominent, oblique and 

 slightly curved tooth ; umbilicus rather 

 wide, deep. 



Remarks. — This species is widely dis- 

 tributed, having been found in Florida, 

 and in the western states. In the former 

 region it is very small, in the latter very 

 large. In Vermont it is of an interme- 

 diate size. 



Helix lahyrinihicn. — Say. 

 Description. — Shell small, elevated 

 conic above, flattened below, with very 

 coarse, regular, oblique incremental strife, 

 so crowded that the intervening spaces 

 are rounded ribs, which are obsolete be- 



neath ; epidermis brown, sometimes in- 

 clining to horn color ; whorls six, convex, 

 with a well impressed suture ; labrum 

 tiiickened, reflected, and usually reddish 

 brown; inner margin with two compress- 

 ed, perpendicular, parallel teeth, which 

 are prolonged into the thro.at of the aper- 

 ture, resembling the track of a rail road ; 

 but the lower tooth is smaller, and some- 

 times obsolete; umbilicus narrow and not 

 deep. Greatest breadth 0.1 inch ; least 

 breadth 0.08 inch ; height 0.08 inch ; di- 

 vergence 135° in the upper third, half aa 

 much below. 



Remarks. — This beautiful little shell 

 is at once distinguished by its peculiar 

 teeth. The aperture is sometimes of an 

 elegant red color. It is found under 

 leaves in the forests, and at the foot of 

 limestone ledges. It occurs as far west 

 as Council BluSs. 



Helix indcnlata. — Say. 



Description. — Shell much depressed, 

 convex above, shininor, of a pale horn col- 

 or, nearly transparent, with distant, near- 

 ly equi-distant impressed transverse lines, 

 of which there are 25 to 30 ; there is often 

 an impressed line parallel with and imme- 

 diately below the suture; whorls four and 

 a half, slightly convej;, with a distinct 

 impressed suture, and rapidly enlarging; 

 aperture large ; labrum sharp, terminating 

 beneath at the centre of the shell, where 

 is-a deep indentation rather than umbili- 

 cus. Greatest breadth 0.1$ inch ; least 

 breadth 0.15 inch ; height 0.08 inch; di 

 vergcnce 160" . 



Remarks. — This species resembles H. 

 arhoreu, Say, but is distinguished by its 

 distant impressed lines, by the enlarge- 

 ment of the last whorl, and the want of 

 an umbilicus. It is rare. 



Helix ariorea. — Say. 



Description. — Shell somewhat de- 

 pressed, convex above, shining, of a pale 

 iiorn color or brown, nearly transparent, 

 with very fine crowded incremental stria;; 

 whorls nearly five, convex, with a well 

 impressed suture ; aperture a little modi- 

 fied by the intrusion of the penult whorl ; 

 labrum sharp ; umbilicus deep, about three 

 fourths as wide as the last whorl. Great- 

 est breadth 0.3 inch ; least breadth 0.26 

 inch ; height 0.15 inch ; divergence 135°. 



Remarks. — This very common species 

 is found both in a dry and in a wet sta- 

 tion. In the former, the shell and the 

 animal are of a pale horn color, and. smal- 

 ler. In the latter the shell is brown, and 

 the animal nearly black. The dimensions 

 above given are of a large specimen of 

 the latter varietj'. The species is very 



