56 



THE MUSCLES. 



hinder ang-le of the orbit, passes along its inner wall, and is in- 

 serted into the antero-internal part of the circumference of the 

 eyeball. 



4. M. rectus superior (Fig". 49 rs.\ 



Dugès, post-orbito-sous-oculaire. 



Arises by a slender tendon from the frouto-parietal bone, widens 



rapidly, and runs forwards and out- 

 wards to be inserted into the upper 

 part of the circumference of the bulb us. 



Fig. 49. 



Eye-muscles of Rana csculenla, froiu 

 above. 

 ti Meiubratiii nictitans. 

 n' Tendon of membrana nictitans. 

 p M. pterygoideus. 

 rs. M. rectus superior. 

 t M. temporalis. 



5. M. obllquus inferior (Fig-, 48 oi). 



Dugès, pré-sous-orbito-oculaire. 



This muscle arises near the floor of 

 the orbital cavity^ at the inner and an- 

 terior ang-le, from the palatine bone by 

 a thin and long- tendon, runs under 

 Harder's gland outwards and back- 

 wards, and is inserted, almost at a right 

 ang-le with the axis of the eye, into 

 the anterior part of the circumference 

 of the eyeball. 



6. M. obliquus superior (Fig. 48 o.v). 

 Dugès, pré-sus-orbito-oculaire, n. 7. 

 The tendon of this small muscle arises from the inner end of the 

 palatine bone, near the origin of the ul, obliquus 

 inferior, runs upwards, backwards, and out- 

 wards, and passes into a flat muscle, which 

 J Xl :a- (^\\ rapidly becomes broader, and is inserted into 



the upper sui-face of the eyeball. 



7. M. retractor buUA (Figs. 48 r, 50 /•, /). 



Dugès, orbito-post-oculaire or clioanide, n. lo. — 

 Zenker, »». opticu». 



This muscle surrounds the optic nerve, and 



is situated within the cone formed by the four 



recti muscles ; it consists of three portions, 



which take their broad and fleshy (the recti 



and obliqui arise by thin tendons) origins from 



the under surface of the parasphenoid. The 



first portion (Fig. 50 r) arises from the under 



surface of the parasphenoid, nearly as far as the 



Fia- 



Eye-muscles of liana cscit- 

 lenta, from below, the m. 

 recti and oblii|ui have been 

 removed. 



n' Tendon of membrana nic- 

 titans. 



r M. retractor bulbi, lower 

 part. 



r' Second part of same. 



