. A manual of zoology. Zoology. I. AMPHINEURA. 35 i mantle extends beyond the shell and is covered with spines, while in the mantle cavity beneath are, right and left, a series of ctenidia. Xerves enter the shell and end with noticeable sense organs (ajs-. 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 work.. Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929. New York, H. Holt and Company