318 University of California Publications in Zoology [Vol.22 



LITERATURE CITED 



Adams, C. C. 



1915. The variations ami ecological distribution of the snails of the genus lo. 

 Mem. Nat. Acad. Sci., 12, part 2, \>\>. 1-92, 61 pis. 



Ball, G. H. 



L922. Variation in fresh-water mussels. Ecology, 3, 93-121, 6 figs, in text. 



BARTSCH, P. 



1906. Variations in the shell of Goniobasis virginica, with an outline for 



breeding experiments (synopsis). Science, n. s., 23, 465 466. 

 L921. A new classification of the shipworms and descriptions of some new 

 wood lioring molltisks. ['roc. Biol. Soc. Washington, 31, 25-32. 



B VI' I ■.. ,(i\, W. 



1889. On some variations of Cardium edule apparently correlated to the con- 

 ditions of life. Philos. Trans. Royal Soc. London, 108 (b), 297-330, 

 pi. 26. 



Burrow, E. I. 



1818. Elements of conchology. Ed. 2 (London, Ogles, Duncan and Cochran), 



.\xiii ; 245 pp., 28 pis. 



Clessin, S. 



1 s;i 7. i lier i li'ii Kiniluss dor I'nigobniig auf die (leh.-iiise der Schncckoii. 



Wurttemburg naturw. Jahreshefte, 53, G6-8G. 



Colton, H, S. 



L922. Variation in the dog whelk, Thais (Purpura And.) lapillus. Ecology, 



3, 1 16 157, tigs, in text. 



Davenport, G. B. 



1904. Comparison of P&cten opercularis from three localities of the British 

 Isles. Proc. Ainer. Acad. Arts and Sci., 39, 123 159. 



Geyer, D. 



1909. Die Weiehtiere Deutschlands (Stuttgart, Streeker & Schroder), viii +- 



1 Id pp., ."> pis., (10 tigs in text. 



(1R1ER, NT. M. 



1919. Morphological features of certain mussel shells found in Lake Erie, 



compared with those of the corresponding species found in the drain 

 age of the upper Ohio. Ann. Carnegie Museum, 13, 145-182, pis. 

 2-3. 



1920. Variation in epidermal color of certain species of Najades inhabiting 



the upper Ohio drainage and their corresponding ones in L. Erie. 

 Amer. Midi. Nat,, 6, 247-2S5, 3 pis. 



Grunsky, C. E. 



1921. Report of the sub-committee on the hydrography of San Francisco Hay, 



in Hepnrt on the San Francisco I Jay Marine Piling Survey, 1, 12-23, 



2 figs, in text. 



