296 THE CILICAGO ACADEMY OF SCIENCES. 
in, forming a distinct furrow and giving the columella the appearance 
of a plait; this is apparent in all of the specimens examined; pillar 
round and smooth, as in obrussa, nearly cylindrical, “the base of the 
preceding whorl abruptly flattened around the insertion of the upper 
end of the pillar.” 
Length. Width. Aperture length. Width. 
23.50 11.25 13.00 8.00 mill. Type 
24.50 11.00 13.50 eb One ut 
25.00 10.50 12.00 iefolo) i 
22.75 10.25 13.00 Epsul(jos 2 Cotype 
21.50 9.50 11.00 bo" ‘i 
20.50 9.00 9.75 450 “ a 
19.50 8.10 9.50 4.10 “ i 
Types: Collection Bryant Walker, thirteen specimens, No, 14347; 
cotypes, Academy of Natural Sciences, Philadelphia; the Chicago 
Academy of Sciences, three specimens, No. 23316. 
Type Locatity: In small spring-brook flowing into Little Tra- 
verse Bay, Petoskey, Michigan. 
ANIMAL, JAW, RApuLA and GeniraALiA: Unknown. 
RANGE: Michigan. Apparently an inhabitant of the Boreal (Ca- 
nadian) life zone and of the Canadian region. 
RECORDS. 
MicuicaAN: Brook, Petoskey, Emmet Co. (Walker). 
GroLocicAL DistripuTion: Unknown. 
Ecotocy: Inhabits a small spring-brook flowing into Little Tra- 
verse Bay. 
Remarks: Petoskeyensis is the largest species of the obrussa 
group of Lymneas. It is at once known by its peculiar inner lip and 
iarge umbilical chink, and by its large size and heavy spiral sculpture. 
Mr. Walker says of it: “This species was at first supposed to be a 
very thin, fragile form of the elongate variety of L. catascopiwm, char- 
acteristic of the lake region. But upon cutting into the shell, the pe- 
culiar shape of the axis forbode its reference to that species.” (See 
Nautilus, p. 6.) 
Petoskeyensis is a very distinct species, not at all likely to be con- 
founded with any other. It is very desirable that the anatomy should 
be examined in order that its correct systematic position may be known. 
It is provisionally placed in Simpsonia, but an anatomical examination 
may place it in Stagnicola with catascopium or emarginata. 
Subgenus STAGNICOLA Leach, 1830. 
1819. Stagnicola Lreacnu, Proof-sheets, pp. 141, 145. 
1819. Omphiscola RAFINESQuE, Journ. de Phys. LXXXVIII, p. 423. 
