. Bulletins of American paleontology. 84 Bulletin 150 230 cross-sections show that the whorls are depressed, the venter being flatter than the dorsum. At the base of the body chamber, the dorso- ventral and lateral diameters measure mm. and mm. respec- tively. Where the dorso-ventral diameter is mm., the lateral di- ameter measures mm., while the siphuncle has a diameter of .4 mm. and is situated .4 mm. from the ventral shell wall. An impressed zone is not developed on the dorsal surface, and the whorls are not in contact. The base of the body chamber is separated from the pen-
. Bulletins of American paleontology. 84 Bulletin 150 230 cross-sections show that the whorls are depressed, the venter being flatter than the dorsum. At the base of the body chamber, the dorso- ventral and lateral diameters measure mm. and mm. respec- tively. Where the dorso-ventral diameter is mm., the lateral di- ameter measures mm., while the siphuncle has a diameter of .4 mm. and is situated .4 mm. from the ventral shell wall. An impressed zone is not developed on the dorsal surface, and the whorls are not in contact. The base of the body chamber is separated from the pen- ultimate whorls by a distance of mm., while the anterior end is separated from that whorl by a distance of mm. The suture is transverse and only slightly sinuous. Irregularly spaced indistinct ribs occur. They are directed posteriorly across the flanks to form a shallow rounded lobe across the venter. Comparisons.—The Western Australian species of Estonioceras differs from typical members of this genus in being more loosely coiled and in possessing weaker ornamentation. Both features may, in part, be a function of weathering and distortion. The whorls are in contact, at least in the early growth stages, in typical members of the genus. It is possible that the whorls of Estonioceras sp. have been separated during distortion of the specimen. The strength of the ornamentation on Estonioceras sp. has been reduced by weathering. Occurrence.—Locality E 10, Emanuel limestone, Emanuel Creek, Kimberley Division, Western Australia. Genus PYCJVOCEKAS Hyatt, 1894 Pycnoceras liratum Teichert and Glenister, PI. 10, figs. 12-15; text fig. 17 Description of holotype (No. 358, Bureau of Mineral Resources, Geology and Geophysics, Canberra).—The holotype and only known representative of the species consists of two-thirds of a well-preserved. Fig. 17. Cross-section of Pycnoceras liratum, X 2J^.. Please note that these images are extracted from scanned page images that may have
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