Parker and Rics—Ox the Myology of Palinurus Edwardsit, Hutton. 173 
Attached to the upper border of the external coxal plate is a strong but slender 
ligament which passes upwards and slightly forwards and outwards to be attached 
to the lower border of a strong sheet of fibrous tissue lining the prostomial plate. 
We propose to call this the anterior coxal Ligament, and consider it to be the vestige 
of a muscle which rotated the coxopodite inwards. 
_ Attached to the posterior border of the external coxal plate is a similar but 
shorter ligament which passes backwards and inwards to unite with the cephalic 
apodeme. We call this the fosterzor coxal hgament : it probably represents a muscle 
which assisted the action of the preceding, or the two may have been the distinct 
heads of a single muscle the tendon of insertion of which has now become the 
external coxal plate. 
Inserted into the upper edge of the internal coxal plate is a strong, slender, 
median ligament which passes upwards and slightly forwards into the apex of a 
pyramidal mass of muscle, the expanded base of which arises from the carapace and 
adjacent parts. This muscular cone is readily separable into two portions: the 
anterior part will be described hereafter as one of the muscles of the eye-stalks, the 
posterior part is bipimnate and arises, on each side, by two heads, one from the 
prostomial plate just below the ophthalmic fenestra, the other from the anterior 
region of the carapace near the middle line. We call this muscle the sapertor coxal 
muscle, and its ligament the median coxal ligament : it probably served to rotate the 
coxopodite outwards. 
The last of these interesting vestiges of a vanished musculature is a narrow 
band of muscle which arises from the carapace below the origin of the external 
adductor of the mandible, curves round the antero-external region of the mandible, 
and is inserted into the posterior edge of the pseudepistoma near its outer end. This 
external coxal muscle, although not reduced to ligament, must be quite functionless, 
since its ends are attached to two structures which are incapable of movement upon 
one another. 
The coxopodite being fixed, the muscles which move the antenna as a whole are 
those of the basipodite. The axis of articulation is oblique, so that its two movements 
are a combination of elevation with abduction and of depression with adduction. We 
shall speak of the muscles as levators and depressors. 
The superior levator arises from the inner surface of the carapace just above the 
origin of the external adductor of the mandible. Its fibres converge into a strong 
calcified tendon which is inserted into the dorsal region of the proximal edge of the 
basipodite. 
