2195 
660 
2200 
2615 
661 
662 
663 
2617 
2616 
1399 
1228 
1227 
664 
2027 
261 
130 
461 
461 
665 
2619 
2618 
666 
667 
214 
Variety loxia Dall. 
Astarte undata? Gould. 
Astarte vernicosa 
Asthenotherus villosior Cpr. 
Astralium inzequale Martyn. 
Astralium (Uvanilla) regina Stearns. 
Astralium undosum Wood. 
Astrea inzqualis 
Astrea undosa 
Astyris aurantiaca Dall, Am J Con 7:115 (1871),t 1518. 
_ Astyris carinata Hinds. 
Astyris tuberosa Cpr. 
Atlanta peroni Lesueur. 
Atrina Oldroydi 
Atys nonscripta A Ad 
Avicula Peruviana 
Axinzea intermedia Broderip. 
Axinzea septentrionalis Middendorf. 
Axinzea subobsoleta Carpenter. 
Axinopsis sericatus Cpr. 
Axinopsis viridis Dall. 
Barbatia gradata Sowerby. 
Barlizea haliotiphila Carpenter. 
Barleeia haliotiphila Cpr 
79 Barleeia subtenuis 
2620 
2695 
2621 
2694 
1218 
668 
669 
670 
2576 
671 
672 
673 
674 
539 
1394 
538 
1395 
2551 
1821 
1946 
2686 
1825 
1827 
1826 
1822 
1824 
1984 
2589 
2001 
1957 
1959 
1828 
1823 
2926 
Genus Bathytoma 
Bathytoma Carpenteriana 
Bathytoma Keepi Arnold. 
Bathytoma Tremperiana 
Bela crebricostata Carpenter. 
Bela exarata Moller. 
Bela excurvata Carpenter. 
Bela fidicula Gould. 
Bela Grippi 
Bela tabulata Carpenter. 
Bela trevelliana Turton. 
Bela violacea Mighels. 
Berendtia taylori Pfeiffer. 
Beringius aleuticus Dall. 
Beringius crebricostatus Dall. 
Beringius frielei Dall. 
Beringius? kennicottii Dall. 
Genus Bifidaria Sterki. 1891. 
Bifidaria agna 
Bifidaria armifera: eastern U. S. 
Bifidaria Ashmuni 
Bifidaria bilamellata 
Bifidaria hebes (See 1593). 
Variety Mexicanorum Ckll. Mesilla, N. M. 
Forma saxicola Ckli. Near Silver Cliff, Colo. 
Bifidaria hordeacea: Ariz.—N. M. 
Bifidaria hordeacella 
Bif. hordeacella parvidens 
Bifidaria pellucida hordeacella 
Bifidaria pentodon 
Bifidaria perversa 
Forma minor Sterki. Nogales, Arizona. 
Bifidaria Pilsbryana Sterki. 
Bifidaria procera 
Bifidaria procera cristata 
