SKELETON 



35 



three paired bars in the wall of the pharynx behind the skull, two 

 of i which are continued above into that part of the lateral plate 

 which corresponds to the styloid process of the lamprey, and one 



ophth. 



■■40, ■#> 



B. 



Fig. 21. 



Myxine glutinosa, L. A, brain, nerves, and portion of the head skeleton (dotted). B, skeleton 

 of the head, complete only on the right side, a.c, auditory capsule ; a.n, auditory nerve ; 6/-1-3, 

 branchial arches ; cb, cerebellum ; co, cornual cartilage ; cr, nasal ring cart.; d.g, dorsal spinal 

 ganglion; e, eye ;/, facial nerve ; fb, forebrain ; for, foramen; hb, habenular ganglion; &p, 

 hypophysial plate ; hy, ' hyoid 'region ; g.g, gasserian ganglion ; gl, glossopharyngeal ; lb, labial 

 cartilage ; mb, midbrain ; md, medulla ; na.c, nasal capsule ; n.c, nerve-cord ; lit, notochord ; ol, 

 olfactory lobe ; ophth, ophthalmic branch .of trigeminal nerve ; pi, ' palatine,' and pq, 

 ' quadrate ' regions ; sob, suborbital nerve ; sp, spinal nerve ; £i- 3 , branches of trigeminal ; tr, 

 trabecula cranii ; ts, preorbital sensory branch ; y, vagus nerve ; v.r, ventral root of spinal 

 nerve ; 1, 2, 3, 4, cartilages of the tentacles. For the nerves compare Figs. 22 and 25. 



of which joins the cartilage of the ' tongue ' below. Vestigial 

 cartilages are also found near the branchial external openings, 

 whether these are separate as in Bdellostoma or united as in Myxine 

 (Figs. 23, 27). 



The huge rasping organ is provided with a set of large anterior 



