CLASS GASTROPODA 
193 
Type. Margarites cidaris A. Adams. 
Distribution. Deep waters of the west coast of North America. 
Cidarina cidaris A. Adams, 1864 
Plate 91, fig. 7 
Annals and Magazine of Natural History, ser. 3, 14:426. Dali, Proceedings of the 
United States Natiotial Museum, 12; PI. 2, fig. 6. 
M. testa magna, conica, Turcicoidea, tenui; albido-cinerea, nacreo- 
argentato; anfr. nucleosis? .... (decollatis), norm, vii., subplanatis; su- 
turis alte insculptis; superficie spirae tota valde tuberculosa, seriebus tribus, 
alteris postea intercalantibus; peripheria et basi rotundatis, carinatis; cari- 
natis; carinis circ. viii., haud acutis, irregularibus, scabris, baud tuber¬ 
culosis; lacuna umbilicali vix conspicua; apertura subrotundata; labro 
tenuissimo; labio obsoleto; columella arcuata. Long., 1.1; long, spir., .65; 
lat., .75; div., 60. 
Shell conical; spire elevated, subacute; whorls six to seven; four upper 
whorls only slightly convex; lower whorls very convex; surface orna¬ 
mented with spiral rows of nodes which grade into nodose ribs on the 
lower side of the body-whorl; suture deeply impressed; aperture circular; 
outer lip thin; inner lip and columella enameled, the incrustation com¬ 
pletely obscuring the small umbilicus in most specimens. Alt., 40; lat., 33; 
body-whorl, 26.5; aperture, 13 mm.; defl., 66°. (Arnold.) 
Type in United States National Museum. Type locality, vicinity of 
Neah Bay, Washington. 
Range. Kasa-an Bay, Alaska, to Cape San Quentin, Lower California. 
Fossil: Pleistocene, San Marcial; Pliocene, San Pedro. 
Described as Margarites cidaris. 
SECTION SOLARICIDA Dali, 1902 
Cidarina carlotta Dali, 1902 
Proceedings of the United States National Museum, 24:553. 
Shell rather depressed, pearly white, covered with a dense, rather 
fibrous, olive-gray periostracum; nuclear whorls eroded, but the shell 
exhibits about four and a half whorls; sculpture of, on the base eight 
minutely distantly nodulous spiral threads stronger and more distant as 
one proceeds from the verge of the umbilicus to the periphery; peripheral 
spiral separated from another above it by an excavated channel; these two 
are the strongest on the shell, and between the upper one and the suture 
is another much feebler thread; the upper two are all that show on the 
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