LYMNZIDA OF NORTH AMERICA. ADY 
of the type (plate XXX, fig. 29) with juvenile specimens of randolphi 
(plate XLVIII, figs. 7-8) well illustrates the relationship of the two 
species. Additional material of petersi is needed to satisfactorily de- 
termine its position. Until the animal of this species and that of at- 
kaensis is examined the correct position of these species must remain 
purely conjectural. The form of the axis is that of the emarginata 
group of Galba rather than of typical Lymnea. 
Galba atkaensis Dall. Pl. XLVIII, figures 13-14. 
Limnea ovata var. atkaensis Dati, Proc. Nat. Mus., VII, p. 343, 1884. 
Limneus atkinensis Ciessin, Conch. Cab., p. 390, taf. LIII, fig. 11, 1886 
(figure not typical). 
?Limnea ovata Dati, Report Fur Seal Inves., III, p. 544, 1866; Nautilus, 
XIII, p. 132, 1900. 
Lymnea atkaensis Dati, Alaska Moll. p. 66, pl. 2, figs. 7, 9, 1905. 
SHELL: “With about four ovate whorls rapidly increasing, of a 
dark olive sometimes purplish tint, very thin, malleated, miscroscopi- 
cally reticulated, with obscure revolving ridges; the aperture ovate, 
not expanded, the margins thin, that on the pillar narrowly reflected; 
pillar gyrate, pervious, in the early whorls widely so, a condition con- 
cealed in the adult.” (Dall). 
Length. Breadth. Aperturelength. Breadth. 
26.50 16.50 16.50 10.50 mill. 4 whorls, Dall. 
24.00 13.00 14.00 5:20 ee 34 + - 
17.00 11.50 11.20 ety, ee 44 oe se 
22.00 16.00 15.50 9.00 “ Type 29031, 
Types: Smithsonian Institution, two specimens, No. 29031. 
Type Location: See records. 
ANIMAL, JAW, RADULA and GENITALIA: Unknown. 
Rance: Aleutian Chain, Alaska; a species of the Alaskan region. 
RECORDS. 
Lake on the Island of Atka, Aleutian Chain, near Korovin Bay (Dall). 
GEOLOGICAL DistrRiBpuTION: Unknown. 
Ecotocy: Not recorded. 
ReMArRKS: “This form grows in a region containing little lime, 
and the shells are extremely thin and often eroded into holes, which 
exhibit the peculiarities of the axis by which the species is relegated 
to the typical Lymnzas though externally it has much the appearance 
of a small Radix.” (Dall). 
This is a wider species than petersi, with less rotund whorls and a 
shorter spire, and with a rounder aperture. The writer cannot agree 
with Dr. Dall in placing this species in Lymne@a. The axis is more of 
