126 PROFESSOR OWEN ON THE ANATOMY OF 



hyoideus, and which looks like a raphe 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 {ib. i, and PI. XXXIX. fig. 1, i) 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, _;', 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 (PI. XXXIX. fig. 2,j); 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 

 raphe, 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. ],j). 



Constrictor salivaris. — This is a flat subquadrate muscle (PI. XXXVII. 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. I & 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, o), 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 (PI. XXXVII. 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, x, 

 from the sternomaxillaris muscle. The ceratohyal (PI. XXXIX. 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 (PI. XXXIX. 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 



