414 MR. A. SANDERS ON THE [June 9, 
superficial fibres also join those of the opposite side in a raphe cover- 
ing the glosso-hyal. 
Submentalis arises from the inferior surface of the dentary piece 
immediately outside and a short distance behind the symphysis, and 
is inserted into mucous membrane lining the floor of the anterior part 
of the mouth, and into the side of the tongue outside the genio-hyo- 
glossus. 
Thyro-hyoid arises from the basihyal, and is inserted into the 
outer circumference of the thyroid cartilage. 
Cerato-hyoid arises from near the distal extremity of the thyro-hyal, 
and, passing downwards internal to the mandible, it is inserted into 
the segment of the cerato-hyal. 
Omo-hyoid arises from the anterior border of the clavicle for 
about half its length, extending upwards to the claviculo-scapular 
articulation, and, passing forwards and downwards, it is inserted, 
broad and thin, into the posterior edge of the basihyal and thyro- 
hyal. 
Sterno-hyoid arises from the interclavicle thick and fleshy, and, 
passing forwards, spreads out into a thin plane of muscular fibres, 
which is inserted entirely into the thyro-hyal dorsad of the last. 
Sterno-cleido-mastoid arises from the posterior edge of the trans- 
verse apophysis of the interclavicle, and is connected with the anterior 
edge of the sternum by means of a tough membrane; passing upwards 
and forwards across the clavicle, it receives a small muscular slip 
from that bone, and is inserted into the extremity of the exoccipital 
behind its articulation with the os quadratum. 
Temporal is a very thick and powerful muscular mass, arising, 
behind, from the anterior surface of the os quadratum, above from 
the squamosal and parietal, and in front from the frontal; the an- 
terior fibres run directly downwards, the posterior downwards and 
forwards ; and all are inserted into the articular, supraangular, and 
coronoid pieces of the mandible. 
Neuro-mandibular.—This muscle appears to correspond with one 
of that name in serpents. It arises broad from the aponeurosis of the 
back of the head and edge of the complexus, and is inserted narrow 
into the posterior extremity of the articular piece of the mandible. 
External pterygoid arises fleshy from the lower surface of the 
posterior part of the pterygoid bone, and tendinous from the posterior 
border of the anterior part of the same bone; it forms a rounded 
muscular mass enclosing the posterior part of the mandible, and is 
inserted into the external surface of the supraangular, and upper sur- 
face of the posterior part of the articular piece ; this last part also 
arises from the lower end of the posterior side of the os quadratum. 
Internal pterygoid.—A. triangular muscle with its apex directed 
upwards arises from the anterior point of the prootic, and from the 
columella, and is inserted into the inner border of the articular piece 
of the mandible behind the coronary process ; this muscle has no 
connexion with the pterygoid bone. Within this are two remarkable 
muscles ; the more external arises from a point at the lower surface 
of the parietal, just above the articulation of the prootic with the 
