<>{.-. 



Fig. 57 



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

 ante ior spinal nerves of Scyllium canicula. 1-5, the five gill-slits of the left 

 side ar, anterior rectus muscle; 2>r, brachial plexus; C, ligamentous band 

 pass ig in front of the spiracle, and perforated by a mucous canal ; cb, 

 cere ellum ; cbh, cerebral hemispheres ; Hy, hyomandibular cartilage ; io, 

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

 the agus nerve; mb, mid-brain or corpora bigemina ; cl, olfactory capsule; 

 pbr, 4th pharyngo-branchial cartilage ; Pg, cut end of pectoral girdle ; fir, 

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

 branch of a branchia nerve ; rb, restiform body ; rn, olfactory lobe (rhinen- 

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

 supplied by the fourth nerve ; sp, spiracle ; xr, superior rectus muscle ; 

 th, thalamencephalon ; Vis, visceral branch of vagus nerve ; .r-z, occipital 

 nerves ; //, optic nerve; ///, oculomotor nerve ; I'a. I' I la, ophthalmic branches 

 of sth and yth nerves ; Vb, maxillary branch of sth nerve ; I'c, mandibular branch 

 of sth nerve; I'llb, palatine branch of 7th nerve; I'Ifc, post-spiracular 

 branch of 7th nerve ; F//7, auditory nerve ; 1 A', glossopharyngeal nerve ; X, 

 Vagus nerve. 



