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partially divided into two layers, the fibres of the deeper layer 
passing obliquely downwards and outwards, and decussating 
the former. All these investing muscles which you now see 
exposed on one side, must have the effect of moving, bending, 
and curling this organ in every direction ; the animal can thus 
bend it upwards over his head, or downwards between his legs, 
or on either side along his neck. 
*< Qn one side we haveraised these longitudinal muscles, and 
in doing so we perceive some of the principal nerves descend- 
ing in tendinous sheaths or canals. ‘To these nerves we shall 
more particularly allude directly. These sheaths are con- 
nected to the muscular fibres on either side, and resemble the 
tendons of digastric muscles ; there are several laminz of these, 
through and between which the principal nerves descend, and 
are thereby protected ftom the pressure of the contracting 
muscles, as, during the action of the latter, these canals will 
be enlarged rather than diminished. Beneath all these long 
muscles, but intimately united to them, we meet another por- 
tion of muscular structure, which extends from the longitudi- 
nal fibres, and from these tendinous canals obliquely inwards, 
to be inserted into the parietes of the tubes. If we look at the 
upper extremity of the proboscis, which has been cut off from 
the skull, the course of these fleshy fibres is evident; they pre- 
sent a radiated appearance, as they pass from the central tubes 
outwards to be inserted, some into the longitudinal fibres, 
others into the tendinous canals for the nerves just mentioned, 
and others pass between the longitudinal fasciculi to the sub- 
cutaneous aponeurosis. Some have attempted to count the 
number of these muscles, but such an attempt is totally use- 
less. These radiated fibres, by their contraction, can approxi- 
mate the parietes of the tubes to the skin, and at the same 
time compress the general structure of the trunk, and thus 
tend to its general elongation, when the longitudinal fibres are 
relaxed; while by this arrangement, also, circular compres- 
sion or constriction of the tubes is avoided, which must have 
been the effect if the fibres pursued.a circular course. At the 
I a a ee 
