Baker — A Revision of the Limnaeas of Northern Illinois. 21 

 8b. Limnaea Keflex a scalaris Walker. 



PI. I. f. 7. 



Limnaea reflexa var. scalaris Bryant Walker, The Nautilus. 6 : 33. pi. t. /. 

 7. 1892. 



This form is intermediate between the typical reflexa and 

 its variety attenuata. It is in reality a scalariform condition , 

 the whorls being well rounded and divided by a deep suture. 

 The variety does not seem to be very common and is always 

 found, at least in this area, associated with the type. It may 

 be collected sparingly in Lake Calumet and near Joliet. 



9. Limnaea stagnalis Linne.* 



Plate I.f.15. 



Helix stagnalis Linne, Faun. Suecica. 2188. 1761. 



Limnaea jugularis Say, Nich. Encycl. Amer. ed. 1816. (Variety.) 



Limnaea appressa Say, Journ. Phil. Acad. 2: 168. 1821. 



Limnaea speciosa Ziegler, of Rossmassler, Icon. Land & Siissw. Moll. 

 1: 96. pi. 11. f. 50. 1835. 



Limnaea occidentalis Hemphill, The Nautilus. 4 : 26. 1890. (Variety.) 



Limnaea sanctaemariae Walker, The Nautilus. 6:31. pi. 2". /. 4, 5. 1892. 

 (Variety.) 



Shell: Elongated (or oval), ventricose at the anterior end, 

 thin; color yellowish-horn to brownish-black; surface shin- 

 ing, growth lines numerous, crowded, more or less elevated, 

 crossed by numerous fine, impressed spiral lines; apex 

 smooth, brownish horn color ; whorls 6^, rapidly increasing, 

 all but the last two rather flat sided ; last whorl very large, 

 considerably dilated and inflated; spire long, pointed, acute, 

 occupying about half the length of the entire shell (some- 

 times very short); sutures distinct but not very much im- 

 pressed; aperture large, broadly ovate, dilated, particularly 

 at the upper part; peristome thin, acute, in some specimens 

 thickened by an internal callus ; lower part rounded ; colum 



* It seems hardly necessary, or worth the time expended, to name 

 the numerous varieties of this species recognized by European writers, and 

 yet it may be of some interest to tabulate the names of some of these varieties 

 as recorded in the Annales de la Soci^te Malacologique de Belgique, 1872. 

 7 : 81, et seq. These are: sinistrosa, Jeff . (reversed), lutea, maxima, expansa, 

 quadrangulata, alba, erosa, regularis, distorta, aperta, biplicata, costulata, all 

 of Collin; minima, gibbosa, illaqueata, scalaris, aqnarii, arenaria, producta, 

 all of J. Colb.; rosea, Gass., subfusca, major, pumila, turgida, all of Moq. 

 Tan.; reseo -labiata Wolf (Moq.), fragilis L. (Moq.). This list simply 

 shows to what extent the system of varietal naming may be carried. 



