Mr. Frank Stephens of San Diego informs the writer that 

 this mollnsk has appeared in abundance about one of the 

 islands in the Salton Sea since the overflow of the Colorado 

 River into that former desert basin. 



Mountain regions of southern Mexico north in the Pacific 

 drainage and Great Basin to southern Oregon, less frequently 

 in Columbia basin, where it intergrades with cygnea. 



Los Angeles System: (extinct) swamp between Palms and 

 Cienaga, Los Angeles Coastal plain (II. Hannibal) ; artificial 

 pond, Elysian Park Los Angeles (Mrs. T. S. Oldroyd) ; reservoir 

 north of old S.P.R.R. depot, east side of Los Angeles River, 

 Los Angeles (R. E. C. Stearns) ; (extinct) Nigger Slough, 

 Gardena (II. Hannibal) ; (extinct) pond, Country Club grounds, 

 Long Beach (fide II. Lowe) ; Rio Honda, Savannah (R. E. C. 

 Stearns). 



Chino Creek, seven miles south-west of Ontario, San Ber- 

 nardino Valley (R. II. Tremper) fide Berry. 



Creek near Fallbrook, San Diego Mesa (fide C. A. Waring). 



Arizona System: (semifossil) Indio, Colorado Desert (R. 

 E. C. Stearns) fide Stearns, (H. Hemphill), (II. Hannibal); 

 (semifossil) play a south of mouth of Roark Canon (S. Bowers) 

 fide Bowers; (semifossil) Monument 219, International Boun- 

 dary (E. A. Mearns) fide Simpson; (semifossil) New River, 

 Laguna (E. A. Mearns) fide Simpson; (semifossil) Laguna 

 Maquata, Baja California (C. R. Orcutt) fide Orcutt. 



Lower Colorado River (J. LeConte) fide Lea; Oak Creek, 

 Arizona (E. II. Ashmun). 

 "Anodonta" dejecta Lewis Fig I. 



Anodonta dejecta Lewis, Field and Forest, I, 1875, 26; 

 in Yarrow, Rept. Geol. and Geog. Sur. W. 100 Mer. V, 1875, 

 952; A. mearnsiana Simpson, Naut. VI, 1893, 135. 



This Naiad, while agreeing with Anodonta in the absence 

 of hinge teeth, is very different in other respects and belongs 

 to a genus by itself, to be properly diagnosed and named else- 

 where. 



Arizona System: (semifossil) New River, Laguna, Colorado 

 Desert (E. A. Mearns) fide Simpson. 



Ponds, Tucson, Arizona (E. A. Mearns) fide Simpson; 

 Santa Cruz River, Tucson, E. A. Mearns) fide Simpson, (J. F. 

 James) fide Stearns;* San Bernardino Rancho, International 

 Boundary (E. A. Mearns) fide Simpson; San Bernardino 

 River, International Boundary (E. A. Mearns) fide Simpson; 

 Colorado River, International Boundary (E. A. Mearns) fide 

 Simpson; mouth of Colorado River, Mexico (E. A. Mearns) 

 fide Simpson. 



Gonidea angulata (Lea) Fig II. 



Anodonta angulata Lea, Trans. Am. Phil. Soc. VI, 1838, 97, 

 PL XVI, 52 ; Gonidea angulata Hannibal, W. Coast Shells, 1910, 

 304, fig. 289. 



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