34 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
produced above; columella somewhat thickened, with the trace of a 
fold. This is the description of A. Adams’ genus Volvula. 
Type. Volvula acuminata Sowerby. 
Distribution. Britain, Mediterranean, Asia, United States. Fossil: 
Pliocene-Pleistocene. 
Volvulella cylindrica Carpenter, 1863 
Plate 2, fig. 9 
Supplementary Report, British Association for the Advancement of Science, 647. An¬ 
nals and Magazine of Natural History , ser. 3, 15:179, 1856. 
V. testa cylindracea, alba, nitente, striis spiralibus distantibus cincta; 
medio planato, marginibus fere parallelis; antice satis effusa, postice 
subito angustata; canali brevissimo; labro acuto; labio indistincto; plica 
columellari parva, valde declivi. Long., .17; lat., .17. (Carpenter.) 
Shell cylindrical, white, shining, encircled by distant spiral striae; 
flattened in the middle, the margins nearly parallel, rather effuse below, 
suddenly narrowed behind ; canal very short; lip acute; inner lip indistinct; 
columellar fold small, very sloping. (Carpenter.) 
Type in the Boyce Collection. Type locality, Santa Barbara, California. 
Range. Vancouver Island to Gulf of California. 
Volvulella cooperi Dali, 1919 
Proceedings of the United States National Museum, 56:297. 
Shell subcylindrical, white, in the young with a very short spine, the 
adult having the spine obsolete or even absent, involuted, bluntly rounded 
at each extremity, the aperture as long as the shell; surface entirely 
smooth; aperture parallel with the body, very narrow, body with no 
perceptible enamel, pillar very short, thickened, slightly reflected with a 
minute chink behind. Length, 9.5; diameter, 3.6 mm. (Dali.) 
Type in United States National Museum, No. 105501. Type locality, 
Scammons Lagoon, Lower California. 
Range. Point Sur, California, to Scammons Lagoon, Lower Cali¬ 
fornia. 
Volvulella californica Dali, 1919 
Plate 2, fig. 11 
Proceedings of the United States National Museum, 56:298. 
Shell minute, polished, white, elongate-ovate, involved, with a short 
apical spire; axial sculpture of very faint incremental lines; spiral sculp¬ 
ture of microscopic striae near the anterior end; axis imperforate; aper- 
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