LYMNEIDZ OF NORTH AMERICA. 391 
the individuals resemble solida in being roundish and having tumid 
whorls, but the resemblance is superficial, the shells having on the aver- 
age, all the characteristics of catascopium. Several of these specimens 
are figured on plate XL (figures 23-26). Specimens of catascopium 
from Lake Champlain, near Burlington, Vermont, are very thin, with 
rather large shell, and somewhat resemble Lymnea limosa Linné of 
Europe. Currier’s intertexta is a synonyn of catascopium, the Black 
Lake specimens being almost identical (though thinner) with in- 
dividuals from Philadelphia (see plate XL, figures 32-35). Currier’s 
types (a cotype figured on plate XL) are scalariform in character, 
but are otherwise the same as typical catascopium. 
Limnea linsleyi De Kay appears to be an immature form of 
catascopium. It has no relation to humilis, as may readily be seen 
by carefully reading the original description. DeKay especially com- 
pares it with pinguis. Catascopium includes in the synonomy six 
names, mostly founded on its various mutations: cornea, Val., seri- 
cata Ziegler, linsleyi DeKay, pinguis Say, intertexta Currier and 
brown Tryon. With all of its variations, however, it cannot be mis- 
taken for any other species when its characteristics are once under- 
stood. 
Galba catascopium niagarensis Baker. Plate XLII, figures 1-4. 
Lymnea fusiformis Lea, Proc. Amer. Phil. Soc., II, p. 33, 1841; Trans. 
Amer. Phil. Soc., IX, p. 10, 1844; Obs., IV, p. 10, 1848 (not Lymnea fusiformis 
Sows., Mineral Conchology, II, p. 155, pl. 169, 1818, an Oligocene fossil of the 
Isle of Wight). 
Lymnea fusiformis WHEATLEY, Cat. Sh. U. S., p. 23, 1843——Scupper, Bull. 
Nat. Mus., 23, pp. 33, 44, 201, 1885. 
Limnea fusiformis HALp., cover p. 4, No. 6, 1843. 
Limnea fusiformis BinNey, Check List, p. 12, 1860; Land & F.-W. Sh. 
N. A., II, p. 50, fig. 72, 1865—Tryon, Amer. Journ. Conch., III, p. 196, 1867. 
SHELL: Thick, solid, fusiform; periostracum yellowish horn; 
sculpture as in catascopium, whorls five to six, flat-sided, broad, rapidly 
increasing in diameter; spire short, broadly acute, the whorls flat-sided 
or only very slightly rounded; sutures slightly impressed; outer lip 
with internal varical thickening; aperture elliptical, narrow in some 
specimens, about as long as the spire; inner lip rather broad, tightly 
appressed to the columella, completely closing the umbilical region; 
parietal callus very heavy; columella with a distinct but not sharp 
fold, axis twisted. 
