Michoacan, southern Mexico to Rio Grande River, New 

 Mexico, Bonneville Basin, Utah, and the Snake River, Idaho. 



Los Angeles System: (Quaternary) Point San Pedro (D. 

 and R. Arnold) fide Arnold. 



Arizona System: (semifossil) Colorado Desert (J. LeConte) 

 fide Conrad;* (semifossil) Grande Jornada (Webb and Blake) 

 fide Gould; (semifossil) Indio (Davidson) fide Stearns, (R. E. 

 C. Stearns) fide Stearns, (H. Hemphill), (H. Hannibal) fide 

 Hannibal; (semifossil) well, 45', Walters (Davidson) fide 

 Stearns; (semifossil) Walters, (R. E. C. Stearns) fide Stearns, 

 (B. N. Jackson) ; (semifossil) Dos Palmos (R, E. C. Stearns) 

 fide Stearns; (semifossil) Volcano Springs (R. E. C. Stearns) 

 fide Stearns; (semifossil) near Imperial (H. Hemphill); (semi- 

 fossil) playa south of mouth of Roark Canon (S. Bowers) fide 

 Bowers; Flowing Springs (C. R. Oreutt) fide Stearns; (semi- 

 fossil) road from Carrizo Creek to Laguna Mountain below 

 old beach-line (Mrs. C. Stephens) ; Pish Springs, fifteen miles 

 north-west of Salton (C. R. Oreutt) fide Stearns; Dos Palmos 

 Springs, six miles north of Salton (C. R, Oreutt) fide Stearns; 

 (semifossil) Monument 21!), International Boundary (E. A. 

 Mearns) fide Dall. 



Fort Yuma Desert (H. Hemphill). 



Paludestrina longinqua (Gould). 



Amnicola longinqua Gould, Proc. Bos. Soc. Nat. Hist., 1855, 

 130 ;Pomatiopsis intermedia Tryon, Am. Jour. Conch., I, 1865, 

 220, PL XXII, 8 ; Paludestrina stearnsiana Pilsbry, Naut., XII, 

 1899, 124; P. imitator Pilsbrv, loc. cit. 1899, 124; *P. longinqua 

 Stearns, Proc. U. S. Nat, Mus. XXIV, 1902, 284, fig. 2; P. curta 

 Arnold, Mon. Pleist. Plio. San Pedro, 1903, 305, PI. VIII, 2; 

 *P. longinqua Hannibal, W. Coast Shells, 1910, 314, PL III, 11. 



A frequent species in the organic mud of springs, moun- 

 tain streams, cienagas, and lakes, commonly with Corneocyclas. 



Southern Arizona and northern Baja California to 

 northern California and southern Idaho, east to Utah. 



Los Angeles System ; spring at three gulches, north branch 

 of Bell Canon, Simi Hills, Santa Monica Range (II. Hannibal). 



Swamp between Palms and Cienaga, Los Angeles Coastal 

 Plain (H. Hannibal); near San Pedro, fide Pilsbry; (Quater- 

 nary) Point San Pedro (D. and R. Arnold) fide Arnold. 



Spring branch, mouth of Mill Canon (S. S. Berry) fide 

 Berry; mouth of Mountain Home Gulch, Mill Canon (S. S. 

 Berry) fide Berry; Mountain Home Gulch, one and one-half 

 miles below Glen Martin (H. Hannibal). 



Springs, Campo, Cuyamaca Mountains (H. Hemphill) fide 

 Pilsbry; springs, Cuyamaca Peaks (H. Hemphill) fide Pilsbry; 

 Springs, old gold mines (H. Hemphill) fide Cooper; spring, 

 North Cuyamaca Peak (Mrs. C. Stephens). 



Arizona System: *( semifossil) Cienaga Grande, Colorado 

 Desert (W. P. Blake) fide Gould; (semifossil) playa south of 

 mouth of Roark Canon (S. Bowers) fide Bowers; (semifossil) 



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