The pallial line, which is the line of attachment of the mantle parallel to the edge of the shell, is not indented by a sinus at the posterior end.
S, s', Right and left mantle pi.
Shell fusiform, with elongated spire; margin of shell and mantle notched.
Pernidae.-Shell very inequilateral; ligament subdivided; mantle open throughout; anterior adductor absent.
On the under side of the free edge of the mantle are situated the numerous small cutaneous glands which, in the large A plysia camelus (not in other species), form the purple secretion which was known to s the ancients.
Puncturella, mantle and shell with a foramen in front of the apex, British.
After escaping from the genital aperture they find their way into the infra-branchial part of the mantle cavity of the parent, probably by passing through the suprabranchial chamber to the posterior extremity of the gills, and then being conducted by the inhalent current caused by the cilia of the gills into the infra-branchial chamber.
In Discinisca and Lingula there is further a lip-sinus or hollow system of channels which traverses the supporting tissue of the edge of the mantle and contains muscle-fibres.
The coelom then is a spacious chamber surrounding the alimentary canal, and is continued dorsally and ventrally into the sinuses of the mantle (fig.
The upper plumage generally is dark green, but the mantle and rump are crimson, as are a broad abdominal belt, the flanks and many crescentic markings on the otherwise yellow lower parts.