Chap. 6. 



INVERTEBRAL ANIMALS OF VERMONT. 



[DO 



FRESH WATER AND LAND SHELLS. 



Remarks. — This species is interesting, 

 as the only representative in New Eng- 

 land of a family whose species are so nu- 

 meroiLs in the Southern and Western 

 states. Here it is found only on our west- 

 ern border in lake Champlain, where but 

 a few specimens have been obtained. It 

 has some claims- to be regarded as a new 

 species, differing much in its proportions 

 from the type of Say's species. But since 

 specimens from Ohio vary much in their 

 proportions, we have not been satisfied 

 that it is a distinct species. 



FAMILY LIMN^ANA. 

 Genus LimNjEA. 

 Generic Characters. Shell thin, oval or elon- 

 gate; spire elevated, more or less acute ; aperture 

 longer than wide ; margins not continuous ; culu- 

 niclla with a single oblique fold. No opercT.lirm. 

 Animal hermaphrodite, spiral ; head depressed ; 

 tentacles flattened, triangular, short, with the 

 eyes at their base, on the inner front side ; foot 

 thin, oval, shorter than the shell. 



Limneca 7n-^a.^ui)u„. — Say. 



Description. -Shell large, ovate, brown, 

 with coarse incremental striai ; whorls 

 five, convex ; last whorl very large, infla- 

 ted; * suture deep ; spire two-thirds as 

 long as the aperture, whicli is large. 

 Length 2 inches; breadth 1.2 inch; di- 

 vergence of the spire 58°. 



Remarks. — This large and noble spe- 

 cies was originally discovered in the 

 North West Territory, in latitude 4y°. 

 Subsequently it has been found only in 

 Burlington. It is very rare in cabinets, 

 but quite recently the author of this 

 work discovered a large number in Bur- 

 lington, at a low stage of the water. 

 LimiKTO, ajiprrysa. — Say. 



Description. — Shell large, thin, horn 

 color, elongate ; whorls seven; upper ones 

 planulate, lower ones convex, last one 

 much eillarged and obtusely shouldered 

 above ; suture not much impressed ; spire 

 long, slender ; ape.x acute ; aperture long- 

 oval ; margin thin aud sliarp ; columellar 

 fold strong,, lieiiirth 1 .?'> inch; breadth 

 0.75 inch; divergence of the spire above 

 33", below 4!)". 



REMARKS:-Tiiis Species has been found 

 for the most part with the preceding at 

 Burlington. Its claims to be regarded as 

 distinct from the L. sfagnaUs, of Europe, 

 are very slight. 



* Whorl;* inadvertently made to levolve the 

 wronw way in our figiKo. 



'¥tt I. 20 



Limnaa graci/is. — Jay. 



Description. — Shell very long and 

 slender, pale horn color; whorls four and 

 a half, very oblique, slightly and regular- 

 ly convex; suture not much im])ressed ; 

 aperture more than half as long as the 

 spire, long-oval ; labium entirely separate 

 from the penultimate whorl, moderately 

 reflected, with a large rima behind it, as 

 strong as the labrum. Length 1 inch; 

 breadth 0.18 inch ; divergence of spire 18'\ 



Remarks. — This extremely rare spe- 

 cies was discovered by Prof. Benedict, in 

 Lake Champlain, at Crown Point. Ono 

 or two specimens have been found on the 

 Vermont side of the lake. The shell is 

 remarkable for its length, which is nearly 

 six times the breadth, although the whorls 

 are very few. The development of the 

 labium is also very remarkable. No oth- 

 er species can be compared with this. 

 Linmcca jialli'la. — A dams. 



Description. — Shell moderately elon- 

 gate, ovate-fusiform, very pale horn color, 

 semi-transparent, not very thin, with fine 

 irregular striae of growth, whorls five and 

 a half, moderately convex ; suture well 

 impressed ; spire fbui--fifths as long as the 

 aperture, acutely conic ; apex sub-acute ; 

 body whorl not much enlarged, somewhat 

 produced below ; columellar fold mode- 

 rate ; umbilicus large. Length 0.48 inch ; 

 breadth 0.22 inch ; divergence of the 

 spire 45°. 



Remarks. — This species is rather com- 

 mon in lake Champlain, clinging to rocks 

 and stones. It has not yet been found in 

 any other region except in Atidover, Ms. 

 It is sometimes nearly white. It difiers 

 from L. desidiosa in having its columella 

 much less tortuous, and its aperture less 

 elongated below the fold. 



LimniEa clodcs. — Say. 



Description. — Shell brown horn-color ; 

 whorls seven, convex; suture well iin 

 pressed; spire longer than the aperture, 

 conic, sub-acute ; last whorl somewhat 

 ventricose ; labium appressed closely to 

 the penultimate whorl; columella promi- 

 nent, with a very strong fold. Length 

 1.2 inch ; breadth 0.55 inch ; divergence 

 of the spire 45°. 



Remarks — Limv<ra vinlrosa, Say, is 

 probably only a variety of this species, its 

 principal difference consisting in the fee- 

 bleness of its columellar fold, which is, in 

 this species, of a variable character. This 

 variety is much more abundant in Ver- 

 mont than the type of L. elodcs. This 

 species differs from L. desidiosa chiefly 

 in not having the columella produced in 

 a straight line below the f"old : from L. 

 jniUidu in the les3 propdi'tional size of the 



