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CONCHIFERA. 
riably soft, and the mouth is situated near the left side of the 
hinge. 
Lamarck divides this class into the two following orders:— 
I. Monomyaira, with one muscle of attachment; shell exhibit¬ 
ing interiorly but one subcentral muscular impression.—II. Di- 
MYAiRAj having at least two muscles of attachment; the shell 
exhibiting interiorly, two separate, lateral, muscular impressions. 
ORDER I.—MONOMYAIRA. 
The animal provided with one muscle of attachment, leav¬ 
ing a nearly central muscular impression. 
Section I. — Without a ligament, or unknown ; or in its stead 
a tendinous chord, which connects the valves. 
TRIBE I.-BRACHIOPODA. 
Provided with two opposite, elongated, ciliated arms, situ¬ 
ated near the mouth, which are rolled up spirally when the 
animal is at rest; mantle having two separate lobes in front, 
which envelope the body.—Shell bivalve, adhering to extrane¬ 
ous marine bodies, either by the shell itself being in contact 
with them, or attached by a tendinous chord. The shells are 
not quite equivalve, and open by a hinge. 
Genus 1.—LINGULA.— Lamarck. 
Generic Character .—Subequivalve, flat, ovate-oblong, apex 
truncated, slightly pointed at the base, elevated on a fleshy ten¬ 
dinous peduncle, attached to marine bodies ; hinge without 
teeth. 
Lingula anatinu. — The Duck Lingula. 
Plate LXXXVII. fig. 7. 
Shaped like a duck’s bill, with a green, shining epidermis, 
and having a cylindrical pedicle. Four inches long. Inhabits 
the Indian ocean. 
Genus 2. —TEREBRATULA.— Lamarck. 
Generic Character .—Inequivalve, regular, subtrigonal; at- 
