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same form, with the difference of being calcareous, the same 
gentleman found that at the right the second tooth was equally 
ditomous, the accessory piece being also in front. But be- 
sides these sorts of lateral jaws in this section of nereides, 
there is a sort of lower jaw, composed of two symmetrical 
pieces, a little widened into a palate at the extremity, and 
approximated in the medial line ; their posterior extremity 
is implanted in the transverse fasciculus of muscular fibres 
of the buccal mass. 
The communication of the mouth with the rest of the intes- 
tinal canal is direct in the proboscidian nereids, but in the 
unidenticulated species, and particularly in the multidenticu- 
lated, this is not the case. The buccal cavity forms a sort of 
cul-de-sac behind, and the continuation is made with the oeso- 
phagus, by an aperture in the form of a cleft, situated at the 
anterior part of the superior paries. This orifice conducts 
into a sort of pharynx, or enlargement, from which issues the 
intestinal canal. The latter is always extended in a right 
line, from one extremity to the other of the body of the ani- 
mal. We often distinguish there a somewhat short oesopha- 
gus, but much more narrow than the rest, as in the uniden- 
tated species, and moreover some salivary glands, pretty 
long, and a little twisted, and they open considerably behind 
the buccal mass. The stomach, which is of a pretty con- 
siderable diameter, and almost equal to that of the abdominal 
cavity, is sometimes without very distinct enlargements, and 
corresponds to the rings of the body. It is sometimes pretty 
markedly strangulated towards its grooves, and more or less 
dilated into coecal appendages in the enlargements of the 
rings. Its parietes, often very slender, are sometimes, as in 
the Nereis gigas , almost as thick as the skin, so that we may 
easily distinguish in them, as in the latter, two strata of fibres, 
one longitudinal and the other transverse. Often also these 
two parts of the general envelope are strongly connected toge- 
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