The valves of this genus are united by means of a tubular, fleshy, or
membranous peduncle surrounding the narrow part of them, and of which
the base is affixed to marine substances.
Shell covered with epidermis, sub-equivalve, equilateral, depressed,
elongated, truncated anteriorly, summit middle and posterior, without
trace of ligament, but supported at the extremity of a long
fibro-gelatinous peduncle, which attaches it vertically to sub-marine
bodies; multiple muscular impression.
_L. anatina._ The Duck’s-bill Lingula. Pl. 17, fig. 2.
Covered with a green, shining epidermis, shaped like a duck’s bill, and
having a cylindrical peduncle.
CLASS IV.
MOLLUSCA.
TWENTY-TWO FAMILIES.
FAMILY I.
PTEROPODA. Six genera
Some genera of this family are without a testaceous covering, and are
mentioned only for the sake of preserving the family entire.