1918] Packard: Molluscan Fauna from San Francisco Bay 303 
Acmaea persona Eschscholtz var. umbonata (Nuttall) 
Patella wmbonata Nuttall, Reeve (1855), fig. 107. 
Acmaea persona var. umbonata, Pilsbry (1891), p. 16, pl. 2, figs. 25-28; 
Dall (1914b), p. 14. 
Description —This variety is described by Pilsbry (1891) as follows: 
‘‘The prevalent form southward of San Francisco is an oval shell with 
rather spreading sides, the ribs narrow, interspaces wide and flat. Color dark 
olive to blackish, closely flecked with fine white dots, and usually having coarse 
white dashes also.’’ 
This species was recognized by Pilsbry (1891) as occurring at San 
Francisco. Not collected by the Survey. 
Range—San Francisco to San Diego (Pilsbry). 
Acmaea scabra (Reeve) 
Patella scabra Reeve (1855)), pl. 37, fig. 119; Carpenter (1863), p. 650; 
Dall (1878a), p. 47; Pilsbry (1891), p. 13, pl. 3, figs. 38-49. 
Description.—This species is described by Pilsbry (1891) as follows: 
‘¢Shell thin, rounded-oval, depressed; apex situated between the center and 
the anterior third; surface sculptured with close, fine, minutely scaly riblets, 
of which larger ones are placed at regular intervals. Color light yellow, indis- 
tinetly spotted (rarely striped in divaricating pattern) with brown.’’ 
Carpenter reports this species both from the Farallones and from 
San Francisco. It is not uncommon along the shores of San Francisco 
Bay and on the beaches outside the Golden Gate. 
Range.—Vaneouver Island to Lower California (Dall). 
Acmaea mitra Eschscholtz 
Acmaea mitra Eschscholtz (1829-1833), p. 18, pl. 23, fig. 4. 
Securria mitra, Carpenter (1863), p. 650. 
Acmaea mitra, Wood and Raymond (1891), p. 57; Pilsbry (1891), p. 24, 
pl. 3, fig. 50. 
Description.—This species was described by Pilsbry (1891) as follows: 
‘*Shell dull-white, aperture nearly circular, wider behind, in some young 
examples somewhat elongated, oval; form conical, apex erect, nearly central, 
blunt, smooth, posterior surface usually straight, but occasionally a little con- 
vex; exterior smooth, marked with very faint concentric lines of growth; 
devoid of epidermis; margin entire, polished, with a narrow semipellucid rim 
inside. 
‘«Tnternally smooth or furnished with grooves radiating from the apex more 
or less strongly marked. Muscular impressions deep, strong, horseshoe shaped, 
with the marks of the anterior ends of the adductors rounded and broader than 
the rest, connected by a slender impressed line marking the attachment of the 
mantle. Young shells are often furnished with irregular riblets more or less 
