Ch. t. “C. tridentatæ” magnitudine et indole simili; sed teretiore, dense castaneâ, fasciis pallidioribus sub epidermide adhærente ornatâ; anfr. primis gracillimis; vert. nucl. anfr. iii, helicoideis, valde decliviter sito, marginibus spiræ rectis, angustis, haud superante; anfr. norm. xii. planatis, primis tumidioribus, suturis impressis; costis circ. xxviii. rotundatis, validis, circa basim prolongatam haud subito evanidis, anfr. ult. sæpe obsoletis; interstitiis haud æquantibus, haud undatis, haud sulcatis; totâ superficie sub lente minutissime et creberrime spiraliter striulatâ; aperturâ ovali, columellâ parum contortâ, labro intus tenui, haud dentato.
Long. 0·55, long. spir. 0·43, lat. 0·13, div. 17°.
Hab. S. Pedro, S. Diego, Monterey; rare. Cooper.
One specimen, in Dr. Palmer’s consignment, is known from Ch. tridentata by the very effuse spire, prolonged base, and crowded ribs without waved sculpture between.
Chemnitzia subcuspidata, Cpr. State Collection, No. 670, a.
Ch. t. parvâ, minus tereti, cerinâ seu purpureo-fuscâ; anfr. nud. ii. et dimidio, valde decliviter sitis, marginibus spiræ parum excurvatis superantibus; norm. viii. planatis, suturis excavatis; costis radiantibus circ. xviii. acutis, circa basim prolongatam vix continuis, ad suturas valde elevatis, subcuspidatis; interstitiis latioribus, undulatis; sulcis spiralibus creberrimis, altis, in spirâ circ. x., costas vix secantibus, circa basim impressis; peritremati vix continuo, labio distincto; columellâ vix tortâ.
Long. 0·23, long. spir. 0·16, lat. 0·06, div. 25°.
Hab. S. Diego; 25 dredged in shoal water. Cooper.
Differs from the figure of Ch. tenuicula (which represents a shell with more numerous ribs than the diagnosis) in its more distant ribs with broader interstices; closer and deeper spiral sculpture; impressed sutures; and especially by the elegant murication of the tops of the ribs, with projecting, curved lines between. This is best seen in the young shells, when the ribs are distinct over the base.