RINGED-WORMS. 209 
by the Annulata, he preferred to place these last at the top. We 
are quite as ready to acknowledge that Articulates with articulate feet 
form a single connected series, and would not therefore separate 
them from each other; but we place the Annulata below the Insects, 
not above the Crustaceans. This arrangement, formerly adopted by 
us when it was less common, appears now to be generally received; 
even by Frenchmen, as, for instance, Minne Epwarps. 
The body of ringed-worms is generally much elongated and 
cylindrical; in some instances it is broader and oval. It is divided 
by transverse folds into rings or girdles, which, in most species, are 
very numerous, and in one and the same species may vary greatly 
in number, at least when that number is very great. The common 
Leech has about 100 such, Eunice gigantea above 400; in Phyllo- 
doce laminosa Sav., AubourN and Mitne Epwarps found nearly 
500 rings, whilst in other individuals of the same species there 
were sometimes only 800. The integument is always soft, not 
corneous, but some of them live in sheaths or shells, sometimes 
compacted with bits of shell or grains of sand into a mosaic work 
of considerable strength, and sometimes consisting of calcareous 
matter, as in the genus Serpula. 
In some the head is not distinct from the succeeding rings of 
the body. In others it is distinguished from the trunk by its 
different form, and is provided with eyes and even with threads, 
which many authors name Antenne, after the so-named parts in 
Insects and Crustaceans; but they differ from these, and can be 
pushed in and out like the horns or feelers on the head of snails. 
The number of these feelers differs; there are rarely more than five, 
and some species have only a single thread of the kind. 
On the rings of the body spines or hairs are usually set, which 
however may be entirely wanting in some, as in the leech. In 
most the hairs or spines are placed upon minute lateral tubercles, 
which may be considered as rudiments of feet. These rudimentary 
feet are, however, never jointed as in insects. They are usually 
divided into two parts, which may be named oars or fins; one on 
the dorsal surface, another on the ventral surface (xame dorsale et 
rame ventrale SAvIGNy). On each of these two projections a 
bundle of hairs (sete) is set, of very different form; and, besides this, 
each projection has, as the rule, a conical spine that can be re- 
tracted into its sheath and is called needle (acus). Moreover, at the 
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