68 LAND AND FRESH WATER MOLLUSKS 



Ljnnnaea (Radix) mighelsi Binney. 



Ldmncrii decollata Mighels, Proc. Boston Soc. Nat. Hist., i, p. 49, 1841. — 

 MiGHELS and Adams, Boston Journ. Nat. Hist., iv, p. 336, pi. iv, fig. 13 

 (four views), 1842. 

 Limnea catascopium Haldeman, Men. Limn., p. 52, 1842; not of Say. 

 Limnaus decollatus KiJSTER, Conch. Cab., ed. 11, Mon. Limn., p. 45, pi. 



VIII, figs. 1 1-14, 1862. 

 LimncEa amphi Mighels, Boston Journ. Nat. Hist., iv, p. 347, pi. xvi, figs. 

 \a~ic, April, 1843 ; not of Hartmann, 1842. — BiNNEY, Land and Fw. 

 Sh. N. Am., II, p. 30, figs. 34-35. 1865. 

 Uninaa mighelsi, W. G. Binney, Land and Fw. Sh. N. Am., 11, p. 31, foot- 

 note, 1865. 

 Limnaa angtilata Sowerby, Conch. Icon., xviii, Mon. Limnaa, pi. vii, fig. 



47, Dec, 1872. 

 Limtiaa emarginata Say, var. mighelsi Binney, Nylander, Distr. of Limjiaa, 

 etc., pis. i-iv, 1 90 1. 

 Range. — Aroostook Co., Maine; Province of Qiiebec ; northern 

 Michigan .'' 



Aroostook Co., Maine! Brome Lake, Province of Quebec! Lake 

 Namakan, north of Lake Superior, western Ontario ; Lake of the 

 Woods, Manitoba. 



The earliest name of this species is decollata.^ which was applied to 



a stunted variety living in acidulous water which destroyed the early 



whorls. This name, however, being quite inapplicable to the normal 



shell, would best be kept for the shells to which it was 



applied, and retained in a varietal sense. After an 



examination of Say's types of L. emai-ginata I am 



quite confident, as species go in Lymnesa^ that it is 



distinct from the present form, which I have never 



seen from the Western region. This species, L. 



Fig. 45. Lym- ^^igjiglsi^ is apparently a representative of Radix, 



ncea mighelsi, \. , ., , .... , ,, ^ i- • .. n • 



while the thickening of the outer hp internally in 



L. emarginaia var. canadensis leads to the suspicion that it is 

 related to Stagnicola. Owing to the manner in which various forms 

 of emarginata have been summarily united with L. mighelsi by rep- 

 utable students, I shall on the present occasion waive this doubt and 

 proceed to its immediate consideration. It may, however, be pointed 

 out that W. G. Binney seems to have been of the same opinion when, 

 in 1S65, he placed L. emarginata in the same group as L. falustris. 



Ljnnnaea (Stagnicola.?) emarginata Say. 



Lyvtneus emarginatus S\\, Journ. Acad. Nat. Sci. Phila., II, p. 170, 1821 ; 



Long's Exp. Rep., 11, p. 263, 1824 (Maine). 

 t Limneus emargina/us Say, Am. Conch., VI, pi. 55, fig. I, 1834. 

 Limneus ontariensis Muhlfeldt in Kiister, 1^62, fide W. G. Binney, op. ciX., 



p. 52, 1865. 



