354 THE CHICAGO ACADEMY OF SCIENCES. 
Limnea subulata Binney, Check List, p. 12, 1861; L. & F.-W. Sh. N. A., 
II, p. 42, fig. 54, 1865; Journ. de Conch., XV, p. 427, 1867. 
SHELL: Elongated, turreted, narrow, thin; periostracum yellow- 
ish to reddish horn; surface shining, marked by close set lines of 
growth which are crossed by fine, wavy, impressed spiral lines; the 
growth lines are sometimes raised into fine ridges, especially on the 
last whorl; nuclear whorls 1%, smooth, round, dark colored, in out- 
line like those of reflexa; whorls 6-714, regularly increasing, flat-sided ; 
spire long and attenuated; sutures not deeply impressed, sometimes 
bordered by a white line; aperture ovate, oblique, somewhat expanded 
in some specimens; peristome thin, the internal rib scarcely developed ; 
inner lip narrow, reflected over and nearly closing the umbilicus, leav- 
ing a small chink; parietal callus wide and tightly appressed to the body 
whorl; columella with a distinct, strong, ascending plait; the aperture 
is sometimes a little reflexed as in some forms of reflexa; the axis is 
twisted. 
Length. Width. Aperture length. Width. 
24.00 8.00 9.00 3.50 mill. Say’s type. 
19.00 7.50 9.50 Shitg) | 2 as 
26.50 10.50 10.50 6.00 -“ Mexico City. 
18.50 7.00 9.00 9:00 * S a 
18.00 6.00 ° 7.00 00) oe os 
22.00 9.00 10.00 AOU Tacs gi s 
21.25 7.00 8.00 . 3:00'— 4 a x 
34.50 14.50 13.00 550. Lake Chalco. 
35.00 12.00 12.50 S00) gis ay + 
Types: Attenuata, Academy of Natural Sciences, Philadelphia, 
two specimens, No. 58572. Subulata, turritus and mexicanus, location 
not ascertained. 
Type Locarity: Attenuata, Mexico City; subulata, Zimapan, 
Hidalgo; turritus and mexicanus, Mexico. 
ANIMAL, JAW, RApULA and GENITALIA: Not examined. 
RANGE: Mexican plateau. This species is found in the Lower 
Austral and Upper Austral life zones. 
RECORDS. 
Hipatco: Zimapan (Dunker). 
Mexico: Lake Chalco, City of Mexico (Baker; Heilprin; Strebel) ; Uhde, 
Lake of Mexico (Dunker) ; City of Mexico (Deppe and Schiede; Say); Lagos 
de Tezcuco, City of Mexico (Phil. Acad.) ; Tlalpam, City of Mexico (Pilsbry; 
Rhoads). 
GEOLOGICAL DistRIBUTION: Unknown. 
EcoLocy: Attenuata lives along the shores of the shallow lakes, 
in water from a few inches to a foot or more in depth; the shells are 
usually found on the muddy bottom or in shore vegetation. 
