The Cambridge natural history . —Shell straight or slightly curved,aperture simple, l;)ody-cliamber large; siphuncle cylindrical, The classification is tliat of Foord, Catal. Fossil Ccphal. Brit. Mus., 1888. 394 NAUTILOIDEA. position variable. Single genns, Ovthnceras (Fig. 254).—Cam-l)rian to Trias. .FA:\r. 2. Endoceratidac.—Shell straight, siphuncle wide, mar-ginal, septal necks produced into tubes fitting into one genera : Endoceras (specimens of which occur six feetlong), and Piloceras.—Ordovician. Fajl 3. Actinoceratidae. —Shell straight or slightly curved, siphuncle wid
The Cambridge natural history . —Shell straight or slightly curved,aperture simple, l;)ody-cliamber large; siphuncle cylindrical, The classification is tliat of Foord, Catal. Fossil Ccphal. Brit. Mus., 1888. 394 NAUTILOIDEA. position variable. Single genns, Ovthnceras (Fig. 254).—Cam-l)rian to Trias. .FA:\r. 2. Endoceratidac.—Shell straight, siphuncle wide, mar-ginal, septal necks produced into tubes fitting into one genera : Endoceras (specimens of which occur six feetlong), and Piloceras.—Ordovician. Fajl 3. Actinoceratidae. —Shell straight or slightly curved, siphuncle wide, contracted atthe septa by genera : Actinoceras,Discosorus, Huronia, Sactoceras.—Ordovician to Carboniferous. Fam. 4. Gom^lioeeratidae.—Shell globular, straight or con-siderably curved, aperture nar-rowed, T-shaped, body-chamberlarge, siphuncle varialjle in posi-tion. The aperture is in somecases so narrow that proljablyonly the arms could be pro-truded. Principal genus, Gom-(sijsi); B, portion of the exterior of n^hoceras (Fig. 255).—Silurian. Orthoceras annidatiim Sowb., x i. r a ? i oi n (Woodwardian Museum, Cambridge.) JAM. 5. AscOCeratldae. Shell sac-like or flask-sh
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
