... Report on the Turton Collection of South African Marine Mollusks: With Additional Notes on Other South African Shells Contained in the United States National Museum

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U.S. Government Printing Office, 1915 - Mollusks - 305 pages

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Page 206 - A Catalogue of the Shells contained in the collection of the late Earl of Tankerville, arranged according to the Lamarckian conchological system, together with an Appendix containing descriptions of many new species.
Page 189 - ... to the axial ribs the whorls are marked by four equal and equally spaced slender spiral cords, which are a little less strong than the ribs, and render the junction with these nodulous. Sutures channeled; periphery and base of the last whorl well rounded, the latter marked by six equal spiral cords, which are about as wide as the spaces that separate them. The impressed grooves are crossed by numerous slender axial threads. Aperture ovate; posterior angle obtuse; outer lip thin, pinched in in...
Page 86 - Nuclear whorls small, deeply obliquely immersed in the first of the succeeding turns, above which the tilted edge of the last turn only is visible.
Page 55 - ... the incised spiral grooves becoming a little more closely spaced toward the anterior end. Of these grooves, 10 are present on the base. Aperture ovate; posterior angle obtuse; outer lip thin, showing the external sculpture within, rendered slightly wavy by the sculpture; columella oblique, slightly curved, reflected over and appressed to the base; parietal wall covered by a thin callus. The type, Cat. No. 249738, USNM, comes from Port Alfred (Coll. No. 1010). It has six postnuclear whorls, and...
Page 15 - The postnuclear whorls are moderately rounded and crossed by rather retractively slanting axial ribs, which are about as wide as the spaces that separate them. Of these ribs 19 occur on the last turn behind the varix, 29 on the penultimate, 31 on the third from the last, 27 on the fourth from the last, 26 on the fifth from the last and 12 on the ribbed portion of the seventh whorl. The parts preceding this are not definitely ribbed. The varix behind the peristome...
Page 120 - ALFREDENSIS. new species. Plate 21, fig. 8. Shell elongate-conic, white. The nucleus consists of a single turn which appears to be smooth. The succeeding turn is well rounded, the next, strongly shouldered on the middle, while the last is slightly concave immediately below the suture, and the rest well rounded. The second whorl is marked with six slender spiral c'ords, which are about as wide as the spaces that separate them. On the following turn a broad cord appears at the appressed summit and...
Page 60 - Aperture broadly oval; posterior angle obtuse; outer lip thin, showing the external sculpture within; columella moderately strong, curved, reenforced by the base, provided with a weak fold at its insertion; parietal wall covered with a thin callus. The type (Cat. no.
Page 157 - ... parietal wall covered with a thick callus, which renders the peritreme complete. The unique type, which was dredged by Mr.
Page iii - The majority of the volumes are octavo in size, but a quarto size has been adopted in a few instances in which large plates were regarded as indispensable.
Page 98 - The spaces inclosed by the, ribs and cords form oval pits, the long axis of which coincides with the spiral sculpture. Sutures channeled. Periphery of the last whorl marked by a moderately broad groove, which is crossed by the continuation of the axial ribs which terminate at the posterior edge of the first basal keel. Base of the last whorl well rounded, marked by six spiral keels which grow successively weaker from the periphery to the umbilical region. The broad spaces between these keels are...

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