CONCHOLOGY. 



Inhabitant aquatic, ferruginous, with 

 numerous yellowish dots ; tentacula dot- 

 ted and flexuous. 



Plate 1. fig. 4. 



Resembles the preceding species in 

 its outline, but differs from that shell in 

 the remarkable umbilicate appearance 

 of its spire ; it is also destitute of those 

 fine parallel raised lines, and is furnished 

 with minute striae, never visible in P. Tri- 

 volvis, the superior part of the lip is more 

 vaulted, and the carina more visible. 



3. P. Parvus. -Shell horn colour or 

 blackish ; whorls four, crossed by minute 

 wrinkles; concave above and beneath, 

 and equally exhibiting the volutions; body 

 generally subcarinate on the margin ; lip 

 rounded, and not vaulted above nor 

 thickened ; mouth within bluish white. 



Breadth one-fifth of an inch. 



Animal aquatic brown, tentacula long, 

 filiform, whitish, with a darker central 

 line, tail rounded. 



Plate 1. fig. 5. 



Probably the same species with that 

 figured by Lister, tab. 139. fig. 45; it is 

 very numerous in the river Delaware, in 

 company with the two preceding shells. 



4. P. Glabratus. Shell sinistral ; whorls 

 about five, glabrous, or obsoletely rugose, 

 polished, destitute of any appearance of 

 carina; spire perfectly regular, a little 

 concave ; umbilicus large, regularly and 

 deeply concave, exhibiting all the volu- 

 tions to the summit ; aperture declining, 

 remarkably oblique with respect to the 

 transverse diameter. 



Breadth nearly nine-tenths of an inch. 



Journ. JLcad. Nat. Sciences, vol. i. p. 280. 



Inhabits South Carolina. 



Presented to the Academy by Mr. 

 L'Hermenier of Charleston, an intelligent 

 and zealous naturalist; he assured me that 

 this species inhabits near Charleston. It 

 somewhat resembles large specimens of 

 the P. Trivolvis, but differs in the total 

 absence of carina, and in having a more 

 smooth and polished surface, as well as a 

 declining and more oblique aperture, and 

 a more profound and much more regu- 

 larly concave umbilicus. 



GENUS LTMX JEA. 



Shells subovate, oblong, or somewhat 

 tapering. Aperture entire, longitudinal- 

 ly oblong, the right lip joined to the 

 left at the base, and folding back on the 

 pillar. 



Observ. These shells, as well as those 

 of the preceding genus, were placed by 



Linnaeus with his Helices, but they offer 

 characters sufficiently distinct, particu- 

 larly their inhabitants. 



SPECIES. 



1. L. Catascopium. Shell thin, horn co- 

 loured or blackish ; whorls four or five, 

 the first large, and generally the remain- 

 der darker and rapidly decreasing to an 

 acute apex, and wrinkled across ; aper- 

 ture large, oval, not three-fourths the 

 length of the shell. 



Length seven-tenths of an inch; breadth 

 nearly one half of an inch. 



Inhabitant yellowish, sprinkled with 

 small, often confluent, paler dots ; tenta- 

 cula two, broad, pyramidal ; eyes black, 

 placed at the base of the tentacula ; tail 

 obtuse rounded or emarginate, not so 

 long as its shell. 



Plate 2. fig. 3. 



It is with much hesitation that we 

 adopt a new specific name for this shell, 

 having always heretofore considered it 

 as the same with the L. Putris of authors, 

 (which hasbeen, perhaps,mistaken for the 

 IfettxLimosaof Linne.) as far as we can as- 

 certain, the principal difference appears 

 to be in the more oblique rerolution of 

 the whorls in the European species, and 

 the more abrupt termination of the spire. 



Inhabits the Delaware river and many 

 other waters of the United States, in con- 

 siderable numbers, and may be found 

 plentifully, during the recess of the tide, 

 about the small streams through which 

 the marshy grounds are drained, in com- 

 pany with several other shells. When 

 kept in a vessel of water, like others of 

 its kind, it will proceed not only up the 

 sides of its prison, but also along the sur- 

 face of the water, the shell downward, 

 with regularity of motion and apparent 

 ease ; in this case the reverted base of 

 the animal is concave ; and as the surface 

 of the water is compelled to a corres- 

 ponding concavity, the pressure of the 

 atmospheric column will account for the 

 sustentation of the animal (whose specific 

 gravity is much greater than that of the 

 water)in this singular position: It occasion- 

 ally crawls to the margin of the water to 

 inhale a supply of air ; with this object the 

 foramen is protruded to the surface, and 

 opened with an audible snapping sound, 

 similar to that produced by the resilience 

 of the nib of a pen. 



There is a species of this genus that we 

 have named L. Jugularis ,- and which, in 

 consequence of its having been found but 

 once, must be considered as a doubtful 

 inhabitant of the United States. It may 



