Fig. 57 



A dissection of the brain, anterior part of the spinal cord, cranial, occipital, and 

 anterior spinal nerves of Scylliuni canicula. 1-5, ,the five gill-slits of the left 

 side ; ar, anterior rectus muscle ; Br, brachial plexus ; C, ligamentous band 

 passing in front of the spiracle, and perforated by a mucous canal ; </;, 

 cerebellum; rM, cerebral hemispheres; Hy, hyomandibular cartilage; io, 

 inferior oblique muscle ; L, post-spiracular ligament ; Ln, lateral branch of 

 the vagus nerve; ;/>, mid-brain or corpora bigemina ; <?/, olfactory capsule; 

 //';-. 4th pharyngo-branchial cartilage ; Pg, cut end of pectoral girdle ; /r, 

 posterior rectus muscle ; ptr, pretrematic branch, and pstr, post-trematic 

 branch of a branchial nerve ; rb, rastiform body ; rn, olfactory lobe (rhinen- 

 cephalon); Sec, horizontal semicircular canal; so, superior oblique muscle 

 supplied by the fourth nerve ; j/>, spiracle ; sr, superior rectus muscle ; 

 th, thalamencephalon ; Vis, visceral branch of vagus nerve ; JT-S, occipital 

 nerves ; //, optic nerve; ///, oculomotor nerve ; Va, Vila, ophthalmic branches 

 of 5th and yth nerves ; Vb, maxillary branch of sth nerve ; Vc, mandibular branch 

 of 5th nerve; /'///>, palatine branch of 7th nerve; VI Ic , . post-spiracular 

 branch of yth nerve ; F//7, auditory nerve ; IX, glossopharyngeal nerve ; X } 

 Vagus nerve. 



