126 PROFESSOR OWEN ON THE ANATOMY OF 
hyoideus, and which looks like a raphé of the muscle. This portion, which represents 
the normal mylohyoideus (h), extends backward as far as the ascending ramus of the 
jaw. A third portion (2b. i, and Pl. XX XIX. fig. 1, 2) arises fleshy from the inner side 
of the ascending ramus of the jaw, whence its fasciculi radiate towards the middle line, 
in a somewhat twisted course, the anterior ones passing beneath the second or normal 
part of the mylohyoideus. The fourth portion, j, at its anterior part arises from the 
angle of the jaw, then from the base of the cranium, and afterward from a strong 
fascia extended thence backwards, between the postcranial prolongations of the nose 
and mouth (Pl. XXXIX. fig. 2,7); the posterior and longest fasciculi come off more 
outwardly and radiate to spread over and blend with the gular fasciculi of the sterno- 
glossi, passing outward and downward, and then bending inward to envelope that 
part of the hyoid apparatus. All the fibres of the fourth portion terminate in a median 
raphé, which is less marked than in the anterior portion. The fibres of the posterior 
division of the mylohyoideus, especially those which are attached superiorly to the under 
surface of the posteriorly prolonged nasal canal, form a kind of muscular sheath for the 
basal part of the muscles of the tongue (ib. fig. 1, /). 
Constrictor salivaris.—This is a flat subquadrate muscle (Pl. XX XVII. fig. 3, k), which 
arises fleshy from the inner border of the base of the ceratohyal, m, passes downward 
and forward beneath the ceratohyoideus, n, expands on emerging, bends over the salivary 
reservoir (figs. 1 & 2, c), and is inserted into the tendon marked * in fig. 2: it also 
blends with the back part of the mylohyoideus. The constrictor salivaris is crossed by the 
ectocarotid (fig. 3, 0), and by the large lingual nerve, u, which, winding round the cera- 
tohyal, m, curves over the ectocarotid and the constrictor, passing forward beneath it 
and the ceratohyoideus muscle, to accompany the sternoglossi to the base of the tongue. 
Ceratohyoideus.—This muscle (Pl. XX XVII. figs. 2 & 3, n) arises from the ceratohyal, 
m, about an inch from its upper end, whence its origin is continued for an extent of 
one inch and a half: its fibres converge and form a fasciculus six lines in breadth, 
which is inserted into the commissural tendon (*, fig. 2), and is connected with a strip, 2, 
from the sternomaxillaris muscle. The ceratohyal (Pl. XX XIX. fig. 2, m), after giving 
attachment to the foregoing two muscles and to the anterior constrictor of the pharynx, 
extends freely forward in front of the scalenus, and mesiad of the sternomastoid muscle, 
its extremity being attached to the stylohyoideus muscle, v. 
Stylohyoideus.—In most mammals, the hyoid arch, by the length of the ossified part of 
the stylohyal and the extent of the ossification of the ceratohyal, is almost restricted to 
hinge- or swing-movements forward and backward upon the proximal joints of the 
stylohyals as a fixed point; so that the basihyal with its immediate appendages— 
usually the tongue—cannot be very far protruded or retracted. In the Myrmecophaga 
jubata the usual place of the stylohyal bone is occupied by a long and slender muscle, 
the stylohyoideus (Pl. XX XIX. fig. 2, v), which arises from the petromastoid, and after 
a course of five inches is inserted into the ceratohyal, here the first bone of the hyoid 
