248 Anatomy of the Rabbit. 



(e) The epiglottic cartilage (cartilago epiglottica) is a trian- 

 gular plate supporting the epiglottis. 



(f) The rudimentary vocal folds (plicae vocales) may be seen as 

 vertical folds of the internal surface of the larynx, especially 

 prominent when the thyreoid cartilage is bent downward on 

 the cricoid. . Each fold forms the posterior boundary of a 

 shallow pouch, the laryngeal ventricle (ventriculus 

 laryngis) . 



In addition to the criothryreoidei, the laryngeal cartilages are 

 connected by several small muscles, including the cricoarytenoidei 

 posterior and lateralis, the thryreoarytenoideus and the arytenoideus 

 transversus, the last named being an unpaired muscle connecting the 

 arytenoid cartilages. 

 11. The eye and related, structures of the orbital cavity. 

 The eyeball should be carefully separated from the bony orbital 

 rim. The first portion of the nasolacrimal duct (d. nasolacrimal), 

 passing from its aperture on the medial surface of the lower eyelid 

 to the lacrimal bone, will be divided. The muscles and glands of the 

 orbit may be made out as follows: 



(a) The levator palpebrae superioris. Origin: Wall of 

 the orbit above the optic foramen. Insertion: Upper 

 eyelid. 



This thin sheet of muscle should be separated from the underlying 

 rectus superior of the eyeball. 



(b) The obliquus superior. Origin: Anterior margin of the 

 optic foramen. The muscle passes upward on the wall of the 

 orbit, then beneath a fibrous cord, the trochlea, which bridges 

 a small portion of the orbital wall and changes the course of 

 the tendon by a considerable angle. Insertion: Antero- 

 dorsal portion of the eyeball. 



(c) The obliquus inferior. Origin: Lacrimal bone. In- 

 sertion: Posteroventral portion of the eyeball. 



(d) The four recti muscles, superior, inferior, medialis, 

 and lateralis, arise from the boundary of the optic foramen, 

 and are inserted respectively on the dorsal, ventral, anterior, 

 and. posterior portions of the periphery of the eyeball. 



(e) The retractor oculi (best seen after the removal of the eye) 

 arises in common with the foregoing recti muscles, and is 



