Chap. 6. 



INVERTEBRAL ANIMALS OF VERMONT. 



157 



FRESH WATER AND LAND SHELLS. 



ovate, with the last whorl larger than the penult ; 

 aperlure longer than wiilo ; with the margins not 

 continuous ; columella smooth, sunictimes trun- 

 cate. No operculum. Animal of the form of ihe 

 shell, with four tentacles, of which the larger are 

 oculiferous. The number of species in this genus, 

 incluclin<: the sub-genus Achatina, exceeds two 

 hundred. But not more than six or eight are 

 known in the United Slates, and only one in New 

 England. 



Bulimus Ivbricus. — Drap. 



Description. — Shell oblong ovate, 

 brown, shining; whorls six, moderately 

 convex ; suture well impressed ; spire 

 twice as long as the aperture, whicJi is 

 ovate; labrum a little thickened witliin, 

 making a little more than a right angle 

 with the columella, which is truncate. 

 Length 0.26 inch ; breadth 0.1 inch ; di- 

 vergence 45° in the upper part of the 

 spire, below it is much less. 



Remarks. — This species, being com- 

 mon over a large part of Europe, is sup- 

 posed by some to have been introduced 

 thence into this country. It is remark- 

 able, on this supposition, that it should 

 liave spread as far as the lake of the 

 Woods and lake Winnipeg. As the di- 

 vergence below tlie middle is very slight, 

 the shell, when half grown, is nearly as 

 wide as when mature. 



Genus Pupa. 



Generic Characters. — Shell cylindrical; ape.v 

 obtuse ; aperture parallel to (he axis of the shell, 

 rounded below, more or less biangular above ; mar- 

 gins reflected, separated bv a lamina ajtpressed on 

 the columella. No operculum. Animal with the 

 form of the .shell ; with four tentacles, of which 

 the larger two are oculiferous at theit summit, 

 and the others are very minute. 



Although a large portion of the exotic species 

 exceed a half inch and many an inch in length, the 

 native species are all minute, and some of them 

 are the least of all our shells. 



Pupa milium. — Gould. 



Description. — Shell ovate, brown, shi- 

 ning, with slight incremental stria,' not 

 discernible without a microscope ; whorls 

 five, convex ; suture well impressed ; apex 

 very obtuse ; aperture horizontally trun- 

 cate above by the penult whorl, indented 

 on the outer lip, with six teeth, of which 

 one is at tlie indenture of the labrum, two 

 very small teeth are in the lower part of 

 the aperture, on the left side is a larger 

 tooth .double at its base, and at right an- 

 gles to this are two on the horizontal mar- 

 gin ; the umbilicus is large. Length 

 0,06 inch ; breadth 0,0.3 inch. 



Remarks. — This species, the least of all 

 which have been described in this coun- 



try, was originally discovered in Middle- 

 bury. Its weight is 0.005 of a grain. It 

 lives under moist decaying leaves, and at 

 tlie foot of limestone ledges. None but a 

 naturalist would find it. 



Pupa ovata. — Say. 



Description. — Shell brown, ovate, ta- 

 pering above the penultimate whorl ; 

 whorls five, convex, with a distinct su- 

 ture ; aperture small, ovate, with an in- 

 denture on the right side ; with six pri- 

 mary teeth, of which two are on the trans- 

 verse lip, viz. a large one on the middle, 

 and a small one to its right ; two are on 

 the left and two on the right side ; some- 

 times a very small tooth is found on the 

 left part of the transverse lip. Length, 

 0.0« inch ; breadth 0.05 inch. 



Remarks. — In color this species resem- 

 bles P. viilium, but is easily distinguished 

 by its size and proportions, and the ar- 

 rangement of the teeth. P. rno(lcstn,Sa.y, 

 for which this species has sometimes been 

 mistaken, is described as having only four 

 teeth. 



Pupa hadia. — Adams. 



Description. — Shell reddish brown, 

 cylindrical, very obtusely tapering in the 

 two upper whorls ; whorls seven, moder- 

 ately convex, with a well impressed su- 

 ture ; aperture orbicular, less than one 

 third of the length of the shell, with the 

 margin slightly reflected, and the sub- 

 margin contracted, with a single rather 

 small tooth on the penultimate whorl; um- 

 bilicus moderate. Length 0.14 ; breadth 

 0.07 inch. 



Remarks. — This rare species was dis- 

 covered by Prof. Benedict at Crown Point, 

 where, only, it has yet been found. Its 

 aperture is wider, and umbilicus less than 

 in P. marginata, Drap. of Europe, but it 

 may be only a variety. It is easily dis- 

 tinguished by its mahogany color. 



Pupa arviifcra. — Say. 



Description. — Shell oblong ovate, of 

 a dingy white, striate ; whorls seven, a 

 little convex, with a moderately impress- 

 ed suture ; apex very obtuse ; aperture 

 subovate, with six teeth, of which the lar- 

 ger on the transverse lip is obliquely elon- 

 gated, and nearly meets the labrum above; 

 one is on the left side, and four are below 

 and on the right side ; of the latter, the 

 first and fourth are the least, and are 

 sometimes wanting. Length 0.17 inch ; 

 breadth 0.0!) inch. 



Remarks. — This is the largest species 

 of Pupa fouiid in the United States, and 

 by its color is distinguished from all which 

 approximate to it in size. It occurs plen- 



