REPORT ON THE SEALS. 211 



The Facial Muscles of Expression. 



These are arranged in the following groups : — The occipito-frontalis, the muscles of the ear, 

 the muscles of the nose, the muscles of the eyelids, the muscles of the orbit, and the muscles of 

 the mouth. 



The Occipito-frontalis in Phoca vitulina. — The specimen from which the cervico-scapular 

 panniculus is described had two V haped prolongations over the frontal region, which represented 

 the occipito-frontal muscles. In another Phoca these fibres extended towards the middle line and 

 touched each other, forming a complete occipito-frontalis. It is supplied by the facial nerve which 

 ascends from the ear over the temporal muscle. In Otaria it is imperfectly formed. 



TJic Muscles of the Ear. — There are three small muscles to the cartilaginous meatus in Phoca 

 vitulina, two small pale fasciculi forming the protractors, and one a retractor. 



The Internal protractor or Attollcns aurem arises from the skin above the middle of the orbit and 

 passes outwards and backwards, and is inserted into the inner and under surface of the cartilaginous 

 meatus of the external ear at the junction of the skin with the cartilage. It is recognised by 

 Humphry ; in Otaria it is indistinct ; in Trichechus the muscle is well developed, but arises 

 posterior to the orifice of the meatus, and is therefore a retractor. 



The External protractor or Attrahens aurem arises from the fibrous tissue over the articulation of 

 the malar with the zygoma, and is inserted into the outer and under surface like the former. It is 

 not noted by Humphry ; in Otaria it is present but undescribed ; in Trichechus it is distinct. 



The Retractor or Retrahens aurem arises from the superior border of the zygoma extending from 

 the osseous meatus, to midway between the articulation of the zygoma with the malar bone anteriorly 

 and the osseous meatus posteriorly. It is inserted into the inner and under surface of the 

 cartilaginous tube of the external ear. It is named the attrahens by Humphry ; in Otaria it is 

 feeble ; in Trichechus it is a strong muscle. 



The Cartilaginous meatus is 1 inch long and S-shaped, the attollens pulls the tube forward 

 and opens it, the attrahens draws it forward and outwards, also opening it. The retrahens retracts 

 the tube and flexes the anterior bend of the cartilage, thereby closing the meatus. They are 

 supplied by the facial nerve. 



The Muscles of the Nose. — The combined Dilator et depressor nasi in Phoca vitulina is rectangular. 

 It arises from the fossa of the superior maxilla on the outer side of the infraorbital foramen, 

 and from above the foramen, extending forwards to the third last molar tooth. The inferior 

 division of the 5th nerve pierces it, and the fibres above the nerve form the dilator nasi, those 

 below the depressor nasi. The former, after crossing the levator anguli oris and the constrictor 

 nasi, is inserted into the side of the nose. The latter is inserted into the side of the nose inferior 

 to the dilator, and into the upper Up, beneath the septum ; some fibres join those of the 

 opposite side, while a few are attached to the skin of the upper lip, coming off from the depressor 

 portion in small slips. The nerve of supply is the facial. 



In Otaria they are described separately. 



The Constrictor nasi (named the compressor in Otaria) arises in Phoca vitulina superiorly 

 from the whole length of the nasal cartilage, and is inserted into the premaxillary bone and 

 muscle of the other side, partly under cover of the levator anguli oris. It is supplied by the facial 

 nerve. 



