. Bulletin of the Geological Society of America. Geology. 318 K. KUEDEMANN MODE OF LIFE OF PRIMITIVE CEPHALOl'ODS with Avide-open apertures. According to the usual procedure, these would be distinguished as different species, the first two as belonging to Oncoceras, the third as a Cyrtoceras. The fact that both the larger and smaller forms with contracted aper- tures exhibit more closely arranged septa just below the living chamber indicates that the contracted apertures actually indicate a gerontic con- dition, and that both forms, the larger and the smaller, had reached or passed maturity. O
. Bulletin of the Geological Society of America. Geology. 318 K. KUEDEMANN MODE OF LIFE OF PRIMITIVE CEPHALOl'ODS with Avide-open apertures. According to the usual procedure, these would be distinguished as different species, the first two as belonging to Oncoceras, the third as a Cyrtoceras. The fact that both the larger and smaller forms with contracted aper- tures exhibit more closely arranged septa just below the living chamber indicates that the contracted apertures actually indicate a gerontic con- dition, and that both forms, the larger and the smaller, had reached or passed maturity. Outside of this difference in size, the two forms agree absolutely in all other diagnostic characters, as relative rate of growth, depth of camerse and septa; and likewise does the third form, with 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 Geological Society of America. [New York : The Society]
Size: 1150px × 2174px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
