82 PROCEEDINGS OF THE ACADEMY OF [VOL. LXXIV 



Natural Sciences Philadelphia, 1913, p. 380-393, text fig. 1-3, pi. 15-10, 

 .Inly, 1913. (Contains some valuable general notes on Micrarionta). 



:19. A new California]! Micrarionta. Nautilus, vol. 33, p. 53, October, 

 1919. {Micrarionta rixfordi n. sp. described from 10 m. west of Twenty- 

 nine Palms). 

 PlLSBRY, H. A., & Ferriss, J. H. 



:08. A now Micrarionta from Arizona. Nautilus, vol. 21, p. 134-130, 

 pi. 11, fig. 0-10, April, 1908. (Paper contains some valuable general notes 

 on genera Micrarionta and SonoreUa). 



SlMFSON, C. T. 



'93. A new Anodonta. Nautilus, vol. 0, p. 134-135, April, 1893. (Ano- 

 donta Mearnsiana n. sp. described from San Bernardino Ranch, Mexican 

 Boundary, Arizona ;= dejecta Lewis). 



'94. T3'pes of Anodonta dejecta rediscovered. Nautilus, vol. 8, p. 52-53, 

 September, 1894. 



3.- — SPECIES COLLECTED IN THE COLORADO DESERT IN 1919 

 AND 1920, WITH NOTES ON OTHERS. 



Source of Material. — In March, 1919, Mr. George Willett 

 of Los Angeles visited the Desert in the neighborhood of Palm 

 Springs and Indian Well, and made a small but interesting collec- 

 tion of land snails, including some "live shells" of Micrarionta 

 wolcottiana, which he kindly turned over to the present writer for 

 study. A year later Mr. Allyn G. Smith of Redlands and Berkeley 

 made a brief stay in the same region. He returned with so many 

 interesting specimens, including the most remarkable find of living 

 wolcottiana hitherto made, that early in April Mr. Smith, Mr. .1. 

 Stanley Ferguson of Redlands, and the writer, with automobile aid, 

 undertook a three-day reconnaissance of the upper end of the des- 

 ert, collections being made at sixteen stations. Although but ten 

 species of mollusks were taken on this expedition, two of these 

 prove to be undescribed, and another constitutes a new record for 

 Hie slate of California. All told, six of the ten species are additions 

 to our list of the; Desert fauna. This material now becomes the 

 principal basis of the present paper, although a series of specimens 

 received from the California Academy of Sciences through the kind- 

 ness of Dr. Barton Warren Evermann, Director, and Mr. W. W. 

 Sargeant, Secretary, and a specimen kindly given by Mr. C. R. Gh- 

 ent i, are also considered. I am happy to acknowledge my indebt- 

 edness to all these gentlemen, as well as to Dr. Emmet Rixford of 

 San Francisco, who kindly loaned me some useful comparative 

 material from his own collection. I am under obligation to Dr. 



