4i 8 SENSE-ORGANS 4ND INTEGUMENT. 



integument which bears two longitudinal ridges projecting into 

 the cavity of the ear, with a broad groove between them. 



The Scutiform Cartilage. Closely connected with the 

 external ear, but not forming a part of it, is the scutiform car- 

 tilage. This lies in the temporal fossa, between the integu- 

 ment and the temporal muscle, just behind the orbit and 

 beneath the craniomedial portion of the auricle (Fig. 63, i, 

 page 97). It is a narrow cartilage about two centimeters 

 long, with its long axis craniocaudal. For the greater part of 

 its length it forms a slender rod, from which a thin cartilagi- 

 nous sheet extends a short distance laterad ; at its caudal end 

 the rod forks, the two arms extending nearly at right angles 

 to the main portion. The scutiform cartilage serves for the 

 origin or insertion of a number of the muscles of the ear. 



Muscles of the External Ear (Fig. 169). (a) The muscles 

 connecting the cartilages of the external ear with other parts of 

 the head have been described (page 96), excepting the tragicus 

 lateralis (4). These muscles are the following: M. intermedius 

 scutulorum (Fig. 63, a), M. frontoauricularis, M. levator auris 

 longus (including the cervicoauricular) (Fig. 63, g, g'}, 

 M. auricularis superior (Fig. 63, k], M. abductor auris longus 

 (Fig. 63, ;/z), M. abductor auris brevis (Fig. 63, /), M. zygo- 

 maticus (Fig. 64, d), M. submentalis (Fig. 64, r), M. depressor 

 conchae (Fig. 64, ^), M. frontoscutularis, M. adductor auris 

 inferior (Fig. 63,/), and M. tragicus lateralis (Fig. 169, 4). 



M. tragicus lateralis (Fig. 169, 4). A band about seven 

 millimeters wide, lying beneath the mass of fat about the ear 

 and running ventrad lengthwise of the concha and close 

 against it. 



Origin (Fig. 96, a, page 229) on the caudal end of the 

 mandibula, in the cavity found between the condyloid process 

 and the angular process. The muscle passes dorsad and is 

 inserted (Fig. 169, 4) on the caudal margin of the tragus and 

 in the depression on the concha just caudad of the tragus. 



Relations. This muscle lies between the temporal muscle 

 and the concha. 



Action. Pulls the ear ventrad and probably rotates it 

 outward. 



