CONCHOLOGY. 



in the young shell ; whorls three or four, 

 striate across with fine, raised, equi-dis- 

 tant, acute lines, forming grooves between 

 them. Spire concave : aperture large, 

 embracing 1 a considerable portion of the 

 body whorl, within bluish white ; lip a lit- 

 tle thickened, internally, and of a red or 

 brownish colour, vaulted above ; umbili- 

 cus large, exhibiting the volutions. 



Length one-fourth of an inch ; breadth 

 one-half of an inch. 



That ingenious naturalist Mr. C. A. 

 Lestteur, found this species of a much 

 larger size in French Creek, near Lake 

 Erie ; breadth three-fourths of an inch 

 nearly ; colours almost black, purplish red 

 within the mouth. 



Plate 2. fig. 2. 



Cochlea, trium orbiiim. Litter, conch' 

 tab. 140. jr. 46. 



Lister figures this shell pretty accu- 

 rately, and it is referred to in Gmelin's 

 Edit, of Syst. Nat. p. 3615, as MbeUa, but 

 it is certainly not that species. 



2. P. Bicarinutut. Shell sinistral pale 

 yellow or brownish, subcarinate above, 

 and beneath translucent. Spire retus- 

 umbilicate, forming a cavity as deep as 

 that of the base. Aperture large, em- 

 bracing a considerable portion of the 

 body whorl, and much vaulted above. 

 Within red brown, with two white lines 

 corresponding with the carina. Whorls 

 three wrinkled, and with minute revolv- 

 ing lines. 



Length one-fourth of an inch ; breadth 

 nearly half an inch. 



Inhabitant aquatic, ferruginous, with 

 numerous yellowish dots; tcntacula 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 

 ofitssp'-rei it is also destitute of those 

 fine parallel raised lines, and is furnished 

 with minute striz never visible in P. 7V- 

 volvi*, the superior part of the lip is more 

 vaulted, and the carina more visible. 



3. P. Parvu*. 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 i lip 

 rounded, and not vaulted above nor 

 thickened; mouth within bluish white. 



Breadth onc-v'' h of an inch. 



Animal aq-.iat.c 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. 



GllM'S l.VMN.KA. 



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. 



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

 loured or blackish ; whorls tour or five, 

 the first large, and generally the remain- 

 der darker and rapidly increasing 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 Europe ; 

 as far as we can ascertain, the principal 

 difference appears to be in the more ob- 

 lique revolution of the whorls in the Eu- 

 ropean 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 

 die marshy grounds are drained, in com- 

 pany with several other shells. When 

 kept in a vessel of wate--. like others of 

 its kind, it will proceed no only up the 

 sides of its prison, but also along 1 the sur- 

 face of the water, the shell J.vw r.ward, 

 with regularity of motion ami .iip;r ent 

 ease ; in tuis case the reverted t >s; of 

 the animal is concave ; an<l as ''.:e surface 

 of the water is compelled to * corres. 

 ponding concavity, the pressure ol the 

 atmospheric column will irrount for the 

 sustentation of the aniinu.', (srhoae specific 



