10 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Diastoma stearnsi Bartsch, 1911 
Plate 73, fig. 3 
Proceedings of the United States National Museum, 39:584; fig. 4. 
Shell elongate-conic. Early whorls and columella light chestnut brown, 
the remaining creamy white. Nuclear whorls decollated, only the last two 
volutions remaining, which are well-rounded and smooth. Post-nuclear 
whorls strongly rounded, marked by low, well-rounded, vertical axial ribs 
which are about as wide as the intercostal spaces; of these ribs sixteen 
occur upon the first, and twenty-four upon the remaining whorls. In addi¬ 
tion to these ribs, the whorls are marked by seven spiral cords, which are 
about as wide as the spaces that separate them and render the axial ribs 
nodulose. The cord at the summit is a little wider than the rest, likewise 
the space that separates it from the adjacent cord and this renders the 
summit of the whorls crenulated. The first subperipheral cord is apparent 
on all the whorls and forms the seventh one, between the sutures. The 
axial ribs usually encroach upon this only feebly, the nodulations therefore 
being less marked than on the spiral cords posterior to it. Sutures strongly 
constricted; periphery of the last whorl and base well-rounded, the later 
marked by six equal and equally spaced spiral cords which are a little less 
than the spaces that separate them. Aperture not quite complete in our 
specimen, broadly ovate, channeled anteriorly; posterior angle acute; outer 
lip thin, showing the external markings within; columella moderately 
strong, somewhat twisted, curved, decidedly reflected; parietal wall glazed 
with a thick callus. Length, 9; diameter, 3 mm. (Bartsch.) 
Type in United States National Museum, No. 32212. Type locality, 
San Diego, California. 
Range. Known only from type locality. 
Diastoma fastigiata Carpenter, 1864 
Plate 73, fig. 1 
Supplementary Report , British Association for the Advancement of Science, 655. 
Annals and Magazine of Natural History, scries 3, 283. Proceedings of the United 
States National Museum, 39:581; fig. 1, 1911. 
B. testa parva, gracili, pallide rufo-cinerea, marginibus spirae vix excur- 
vatis; anfr. nud. iii., laevibus, tumidis, apice acuto; norm, ix., planatis, 
suturis alte impressis; anfr. primis iii., carinatis, postea costis radiantibus 
circ. xiii, obtusis, satis extantibus, ad suturas interruptis, interstitiis undatis, 
liris spiralibus iv., in spira se monstrantibus, costas undatim superantibus, 
quarum antica in testa jun. plerumque extat; anfr. ultimo parum contracto, 
[ 612 ] 
