132 THE CAT. [chap. v. 



Various other muscles act on the ear, which it is not deemed 

 necessary to describe in detail ; suffice it to say they may be grouped 

 into muscles which tend to draw the external ear forwards, inwards, 

 or backwards. Certain muscles pass even from the skin to the ear — 

 the (turiculo-cenicaUs from the skin of the front of the neck, and the 

 auriculo-kibial and the auricuIo-mhniaxiUary from the lips and from 

 the skin beneath the lower-jaw. 



The zygomato-aurieularis passes from the skin of the cheek and 

 from the zygoma backwards to the pinna of the ear externally. It 

 is in part continuous with the zygomaticus. It draws the ear forwards. 



The Aftolentes cmricidam are muscular bundles which pass from 

 the mid- cranial region outwards to the pinna, so as by their con- 

 traction to bring the two ears together. 



The retraJientes auriculam are various muscular {m) bundles which 

 come from the occiput and the cervical region to the pinna, and by 

 their action draw it backwards. 



The eyeball, lying in its orbit, is held in place and moved by 

 seven muscles. 



The first of this is the suspcnsor oculi, or "choanoid muscle," 

 which arises round the optic foramen, and thence expanding and 

 embracing the eyeball, is inserted into rather the posterior surface of 

 the latter. Its fibres are dii'ected longitudinally outwards, and it is 

 more or less divisible into four parts — one superior, one inferior, one 

 external, and one internal. 



External to this muscular cone are four straight and two oblique 

 muscles of the orbit (Fig. 130). 



The four straight muscles, or recti, also arise round the optic 

 foramen, and thence diverging, arc respectively inserted into the 

 upper, inner, lower, and outer sides of the eyeball, whence they are 

 termed superior, infernus, inferior, (Did e.vtvrnus, respectively. They 

 are inserted in front of the insertion of the suspensor oculi, and corre- 

 spond with and are superimposed on the four portions of the latter. 



Each rectus muscle is a fiattened band of parallel fibres, and pulls 

 the eyeball by its contraction either upwards or inwards, or down- 

 wards or outwards. By combining their actions variously, they 

 can move it in any intermediate direction. 



The oh/iqiius fitiperior is also a long and slender muscle arising near 

 the optic foramen. At the inner margin of the orbit its tendon passes 

 through a fibro-cartilaginous ring (or pulley) attached to the frontal 

 bone, and then bends backwards to be inserted between the upper 

 and the external recti muscles. 



The oh/iqiiKK ////rr/or has no pulley, and is the only short muscle of 

 the orbit. It springs from the orbital plate of the maxilla near the 

 lachrymal groove, and passing thence backwards, between the floor 

 of the orbit and the rectus inferior, is inserted into the postero- 

 external aspect of the eyeball. 



The two oblii[uc muscles are so disposed as to draw the eyeball 

 forwards and inwards when they act together, and to rotate it in 

 different ways when they act successively. The upper oblique 



