25 
299 Macoma inquinata Desh 
1176 Macoma lata Gmelin. 
3867 Macoma nasuta Conrad 
889 Macoma obtusa Carpenter. 
890 Macoma sabulosa Spengler. 
366 Macoma yoldiformis Carpenter 
2145 Macrocallista squalida Sowerby. 1835. 
2146 Macrocallista aurantiaca Sby. 1831. 
2147 Macrocallista pannosa Sby. 1835, 
2148 Macrocallista puella Cpr. 1864. 
14 Macrocyclis concava 
2231 Macrochasma crenulata 
2450 Macromphalina Californica 
591 Macromphalina occidentalis 
64 Macron aethiops 
157 Macron lividus A Ad 
891 Mactra californica Conrad. 
289 Mactra falcata Gld 
288 Mactra planulata Conr 
1625 Mactra catilliformis Dall. 
1626 Mactra Hemphillii Dall. 
1627 Mactra dolabriformis Conrad, 1867. 
1628 Mactra polynyma Alaskana 
1635 Mactra (Mactroderma) velota Phil. 1848. 
1636 Mactra (Mactrotoma) nasuta Gld. 1851. 
1637 Mactra (Mactrella) exoleta Gray, 1837. 
16388 Mactra (Macirella) elegans Sby. 1825. 
2526 Magilia perattenuata 
178 Mangilia angulata Cpr 
892 Mangilia bicarinata Couthouy. 
893 Mangilia crebricostata Carpenter. 
2451 Mangilia densistriosa Cpr. 
2452 Mangilia Fancherz 
884 Mangilia funebrale Dall. 
895 Mangilia hemphilli Stearns. 
485 Mangillia interlirata Stearns. 
896 Mangilia hexagona Gabb. 
897 Mangilia interfossa Carpenter. 
898 Mangilia levidensis Carpenter. 
899 Mangilia merita Gould. 
2732 Mangilia Painei 
900 Mangilia sculpturata Dall. 
901 Mangilia striosa C. B. Adams. 
397 Mangilia variegata Carpenter. 
398 Variety Nitens Carpenter. 
2137 Marcia Kennerleyi Rve. 1864. 
2174 Marcia (Venerella) subdiaphana 
394 Margarita acuticostata Carpenter 
902 Margarita canfieldi Dall. 
903 Margarita helicina O. Fabricius. 
904 Margarita lirulata Carpenter. 
2752 Margarita lirulata subelevata Cpr. 
905 Margarita pupilla Gould, 
2753 Margarita pupilla salmonea Cpr. 
2915 Margarita sharpii 
1255 Margarita vahlii Moller. 
3072 Margarites simblus 
907 Marginella Pyriformis Carpenter. 
906 Margarita varicosa Mighels. 
58 Margaritana undulata 
