Xliv.) has classified with appropriate names the various stages through which Brachiopod larvae pass.
The brachiopod body, the 3.
The valves are, consequently, essentially symmetrical, which is not the case with the Lamellibranchiata, - so much so, that certain Brachiopod shells were named Lampades, or lamp shells, by some early naturalists; but while such may bear a kind of resemblance to an antique Etruscan lamp, by far the larger number in no way resemble one.
The soft body of the Brachiopod is in all cases protected by a shell composed of two distinct valves; these valves are always, except in cases of malformation, equal-sided, but not equivalved.
The body of the Brachiopod v usually occupies about the posterior half of the space within the shell.
The water which bears the oxygen for respiration and the minute organisms upon which the Brachiopod feeds is swept into the mantle cavity by the action of the cilia which cover the arms, and the eggs and excreta pass out into the same cavity.