48 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Elephantulum carpenteri Bartsch, 1920 
Journal of the Washington Academy of Sciences , 10:1920. 
This is a large thin shell, in which the segments of all stages are 
marked by very fine spiral sculpture and a little stronger incremental 
lines, while the last portion of these stages bears well-developed annuli. 
These increase in number in succeeding stages. Length, 4.8; diameter, 0.9 
mm. (Bartsch.) 
Type in United States National Museum, No. 340726. Type locality, 
San Diego, California. 
Range. San Pedro, California, to Point Abreojos, Lower California. 
Family VERMETIDAE 
Genus BIVONIA Gray, 1850 
Shell affixed, mostly spiral, aperture contracted, circular, with spiral, 
interruptedly nodulose lirae, and a median elevated line; columella smooth. 
Operculum small, rudimentary. (Tryon, Structural and Systematic Con- 
chology.) 
Type. Bivonia triquetra Bivona. 
Distribution. Mediterranean, Philippines, west coast, North and 
South America, and West Africa. 
Bivonia compacta Carpenter, 1864 
Annals and Magazine of Natural History, ser. 3, 14:427. 
B. testa satis magna, saepe solitaria, purpureo-fusca, spiraliter plerum- 
que satis regulariter contorta, obsoletim cancellata seu sculptura fere 
evanida; testis tenacissime adhaerente. Long, (plerumque), 7; lat., 3; 
diameter aperture, 1 poll. (Carpenter.) 
Entirely open within; but color and growth alike. (Carpenter.) 
Type in ? Type locality, Barkley Sound, Vancouver Island, British 
Columbia. 
Range. Vancouver Island, British Columbia, to San Pedro, Cali¬ 
fornia ; Peru ? 
Genus VERMICULARIA Lamarck, 1799 
Shell free, in its early stage regularly coiled like a Turritella; subse¬ 
quently uncoiled, the tube variously twisted, or.more or less straight and 
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