. Bulletins of American paleontology. 201 AusTRAMAN DRnoviciAN CephALoiHTUs: Tfichkrt &: Glenistkr 55 Geology and Geophysics, Canberra; PI. 5, figs. 1-2).—The holotype is a slowly expanding orthoconic longicone with a length of 60 mm. The conch is weathered across the dorsum, but it is almost certain that the cross-section was circular. The shell diameter is estimated to have been 16 mm. at the posterior end of the specimen and 21 mm. at the anterior end. The siphuncle is marginal and has a uniform di- ameter of mm. Nine camerae together have a length equal to the shell diameter. The s
. Bulletins of American paleontology. 201 AusTRAMAN DRnoviciAN CephALoiHTUs: Tfichkrt &: Glenistkr 55 Geology and Geophysics, Canberra; PI. 5, figs. 1-2).—The holotype is a slowly expanding orthoconic longicone with a length of 60 mm. The conch is weathered across the dorsum, but it is almost certain that the cross-section was circular. The shell diameter is estimated to have been 16 mm. at the posterior end of the specimen and 21 mm. at the anterior end. The siphuncle is marginal and has a uniform di- ameter of mm. Nine camerae together have a length equal to the shell diameter. The shell is smooth. Abrasion of the outer surface of the conch has rendered the accurate tracing of the suture line impossible, but the suture appears to be straight and to slope posteriorly from the venter to the dorsum. A ventral lobe is not developed. The whole specimen has been cut in the dorso-ventral mid- plane, and a thin section made of the posterior 16 mm. The septal necks are subholochoanitic, reaching slightly more than three-quar- ters of the distance to the preceding septal foramen. No textural dif- ferentiation has occurred in the thick connecting Fig. 9. Ectosiphuncle of Lebetoceras Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Paleontological Research Institution (Ithaca, N. Y. ); Columbia University. Ithaca, N. Y. , Paleontological Research Institution [etc. ]
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