= = ee Se ata ee } 
Gz ‘ Oe — 
é : = et ‘AG a 4 
== ne ee ee 
202 - SHELLS OF SAN PEDRO BAY—WILLIAMSON. 
the above and hundreds of specimens, I am compelled to the belief that 
they are sitiply forms of one protean species.” 
Margarita pupilla Gld. 
A dead one reported. 
Genus SOLARIELLA 8S. Wood. 
Solariella cidaris A. Ad. Pl. xxii, fig. 4. 
Dredged in deep water off the islands by the U.S. Fish Commission.’ 
Solariella peramabilis Cpr. 
One or two specimens found. Dredged off Catalina living in 30 
fathoms. Also found fossil. 
Genus CANTHARIDUS Montfort. 
Subgenus HAListyius Dall. 
Cantharidus (Halistylus) pupoideus Dall, Pl. xix, Fig. 2. (Fenella pupoidea 
Cpr., not of A, Adams.) 
Four found in rocky pools at Dead Man’s Island. For an account of 
this genus see these Proceedings, x11, p.341. The original Fenella is a 
Rissoid. 
Family CYCLOSTREMATID 2. 
Genus VITRINELLA Adams, em. 
Vitrinella Williamsoni Dall. Pl. xx1, figs. 2 and 3. 
Shell small, white, depressed, with two and a half whorls; spire flat- 
tened; suture appressed with a shallow channel or excavation outside 
of the appressed margin of the whorl, outside of which the convexity 
of the whorl rises higher than the suture. Base slightly more rounded 
than the upper side, with a wide and flaring umbilicus; periphery 
rounded; aperture rounded, oblique; surface polished, finely striate 
here and there by the incremental lines which are most prominent 
above. Maximum diameter of shell, 5.5; minimum diameter, 4.5; alti- 
tude, 1.25 millimeters. 
Beach at San Pedro; U. S. National Museum, registered number 
106,856. 
This species, which is rather large for a Vitrinella, is respectfully 
dedicated to Mrs. M. Burton Williamson, to whose researches this 
paper is due. The name being inherently masculine, the usual geni- 
tive ending is preserved. 
