054 THE CHICAGO ACADEMY OF SCIENCES. 



Limncea subulata Binnkv. 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 l l / 2 . smooth, round, dark colored, in out- 

 line like those of reflcxa; whorls 6-7^2, 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 





3.50 " 



" " 



26.50 



10.50 



10.50 





6.00 " 



Mexico City. 



18.50 



7.00 



9.00 





9.00 " 



" " 



18.00 



6.00 



7.00 





7.00 " 



" " 



22.00 



9.00 



10.00 





4.00 " 



" " 



21.25 



7.00 



8.00 





3.00 " 



" " 



34.50 



14.50 



13.00 





5.50 " 



Lake Chalco. 



35.00 



12.00 



12.50 





5.00 " 



" " 



Types : 



Attenuate!. 



Academv 



of 



Natural Sciences. Phila< 



two specimens. No. 58572. Subulata, turritus and mexicanus, location 

 not ascertained. 



Type Locality: Attenuata, Mexico City; subulata, Zimapan, 

 Hidalgo; turritus and mexicanus, Mexico. 



Animal, Taw, Radula and Genitalia: Not examined. 



Range : Mexican plateau. This species is found in the Lower 

 Austral and L'pper Austral life zones. 



RECORDS. 



Hidalgo: 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, Cits' of Mexico (Pilsbry; 

 Rhoads). 



Geological Distribution : Unknown, 



Ecology: 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. 



