xi PRACTICAL DIRECTIONS 553 



2. The four recti and the two oblique muscles of the eye. Note the 

 course of the superior oblique through its tendinous loop (p. 534). 



3. The lacrymal and Harderian glands, situated in the postero- 

 superior and antero-inferior regions of the orbit respectively. 



II. Remove the eyeball by cutting through the muscles and optic nerve, 

 noting the retractor bulbi muscle around the latter. (For the dissection 

 of the eye, see p. 555. ) Cut off the pinna, and clear away the muscles, 

 &c., covering the tympanic bone: remove the entire tympanic and 

 periotic bones (p. 492) in one piece, lay open the external auditory 

 passage, and very carefully and gradually cut away the outer wall of 

 both tubular and bulbous portions of the tympanic with the bone- 

 forceps. Note :. 



1. The tympanic membrane and the handle of the malleus ; and after 

 cutting away the former so as not to injure the latter, and removing 

 rather more of the bulla, make out (Fig. 143) 



2. The tympanic cavity ; the malleus, incus, and stapes ; the tensor 

 tympani and stapedius muscles ; and the aperture of the Eustachian 

 tube. Remove the auditory ossicles, noting as you do so the fenestra 

 ovalis and fenestra rotunda, and examine them under the low power 

 of the microscope : by cutting through the periotic with the bone 

 forceps, the position of the membranous labyrinth, including the cochlea, 

 may be made out. 



III. Dissect off the muscles covering the mandible on the side you 

 are working ; detach its ascending portion from the muscles inserted 

 on its inner surface, remove it entire, cutting through the symphysis, 

 and clear away the underlying muscles. Pass a probe from the cut end 

 of the gullet forwards into the mouth : lay open the gullet along this, 

 and pull the tongue downwards, so as to get a view into the interior of 

 the mouth (Fig. 135). Note : 



I. a, The palate and velum palati ; b, the tongiie and its papilla 

 (p. 507); c, the pharynx ; d, the glottis, and epiglottis, embraced by 

 the soft palate ; e, the continuation of the pharynx above the velum 

 palati (naso-pharynx], with which the internal nostrils communicate ; 

 f, the positions of the teeth (incisors and grinders) ; g, the apertures of 

 the naso-palatine canals. 



Then remove the nasal, premaxilla, and maxilla of the same side, 

 noting the olfactory nerves and the turbinals (p. 534) ; and after passing 

 a probe backwards from the external nostril into the nasal chamber as 

 far as it will go, remove the turbinals on this side, so as to expose the 



