44- 



LIMNEA. 



appellation of Limnea; they may be divided into four sec- 

 tions, as follows : 



§ 1. Testa tenuissima, subglobosa, polita; lahio interno dilatato ; aper- 

 lura ovat^, dextra. Animal — Pallium reflexum. Tentacula brevia, trigona. 

 Myxas^ Leach's M. S. Helix glutinosa, Mont. Limnea glutinosa, Drap, 

 Tab. nost. f. 5. 



\ 2. Testa tenuis, obovata, polita : labio interno dilatato ; apertur^ 

 ovata, vel ovato-lanceolata, sinistra. Animal — Pallium reflexum ; tentacula 

 subulata. Physa, Drap. Bullae Linn. 



§ 3. Testa^ tenuis, oblonga, polita ; labio interno externum adequante ; 

 apertura, lanceolata, sinistra. Animal — Pallium non reflexum : Tentacula 

 trigona, Aplexa, Fleming : Physa, Drap. Bulla hypnorum, Linn. 



§ 4. Testa tenuis, plerumque oblonga, solidiuscula; apertura ovali 

 dextra. Labio interno externum adsequante. Animal — Pallium non re- 

 flexum. Tentacula compressa, trigona. Limnea^ Lam. j Helix, Linn. 



The shells of this Genus are inhabitants of rivers, 

 ditches, fresh-water lakes, and stagnant pools, throughout 

 Europe, and in all other parts of the world, particularly in 

 North America, where the late researches of Naturalists 

 have led to the discovery of several species : in the East 

 Indies also, several undescribed species have been lately 

 found; we have given engravings of some of these. The 

 common English species are the L. stagnalis, auricularia 

 palustris, and peregra ; L. elongata and L. glutinosa, are 

 scarce and local : L. fontinalis and L. turrita (Bulla fonti- 

 nalis and hypnorum. Linn.) are not unfrequent : besides 

 these we have some other species of less note. 



Several fossil species of this Genus occur abundantly 

 in company with various Paludinae and Planorbes in the 

 fresh-water formations : these are found in the neighbour- 

 hood of Paris, and in the upper and lower of those forma- 

 tions at Headen Hill, and in other parts of the Isle of 

 Wight : we have also found them sparingly in the mixed 

 stratum commonly called the " upper marine formation" 

 between the two ; but we believe they do not occur in any 

 other. 



Mr. I. E. Gray has favoured us with the two following 

 species of Limnea from the East Indies, which he has named 

 and characterized as follows :. 



1. L. rufescens ; testa oblongo-lanceolata, tenuis, hyalina, purpurascente- 

 rufescens, anfractibus quatuor. Spira brevissima, acuta, suturis perob- 

 liquis". Apertura lanceolata, elliptica. Columella obliquissima. Tab. 

 nost. f. 2. Limnea acuminata ? Lam. vi. pt. 2 p. 160. 



Obs.'"ln its general form this shell is not ovato-ven- 

 tricose, we therefore cannot cite Lamarck with any cer- 



