280 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
spire is marked by narrow spiral cords. The spaces that separate these 
cords are crossed by numerous, very slender, axial threads which give 
them a decidedly pitted appearance. Suture slightly constricted. Periphery 
of the last whorl well-rounded. Base rather attenuated, marked by the 
continuations of the axial ribs and the same type of spiral sculpture de¬ 
scribed for the spire. Aperture large, decidedly oval, with a strongly ex¬ 
panded and thickened peristome; outer lip evenly curved; inner lip almost 
straight and continuing as a heavy callus over the parietal wall which 
renders the peritreme complete. 
Type in United States National Museum, No. 362454. Type locality, 
San Clemente Island, California. Length, 7.8 mm.; diameter, 2.5 mm. 
SECTION MELANELLA (see p. 68) 
Melanella portlandica Bartsch, 1927 
Proceedings of the United States National Museum, 70: 4; PI. 1, fig. 6. 
Shell of moderate size, regularly elongate-conic, milk-white, shining. 
Nuclear whorls decollated in the type. Postnuclear whorls narrow between 
the summit and suture with the summit appressed, very slightly rounded, 
marked at irregular intervals by varicial impressions. Suture only very 
slightly impressed. Periphery of the last whorl slightly inflated, strongly 
rounded. Base very short, strongly rounded. Aperture small, pyriform, 
oblique; posterior angle acute; peristome very much thickened; columella 
short, almost straight, decidedly thickened and reflected over the umbilical 
area as a thick callus; parietal wall covered by a thick callus. 
Type in United States National Museum, No. 362492. Type locality, 
Portland, Oregon. Length, 9.1 mm.; diameter, 3.1 mm. 
The short thickened aperture and short base will at once distinguish 
this from Melanella micans . There is a suggestion of Melanella (Balds) 
thersites but its straight form and general proportions differentiate it 
from that species. 
Subgenus Grapiiis (see p. 83) 
Aclis californica Bartsch, 1927 
Proceedings of the United States National Museum, 70: 4; PI. 1, fig. 2. 
Shell small, pupiform, thin, bluish white. Nuclear whorls not dif¬ 
ferentiated from the postnuclear turns. All the whorls well-rounded, 
appressed at the summit which is finely crenulated, the rest marked by fine 
lines of growth which are somewhat retractively slanting. The type is 
slightly worn and shows no indication of spiral sculpture. Sutures mode¬ 
rately constricted. Periphery of the last whorl inflated and strongly 
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