V. 



THE ORBIT 



151 



and tenth. These nerves all carry ganglia containing the cell bodies 

 of sensory fibres and these are comparable to the spinal dorsal root 



' op prof 



olf.b. 



cbl sip. 



c'd.a. 



Fig. 100. Orbit of the dogfish. 



ant. reel, anterior rectus; cereb. cerebellum; cil.a., cil.p. anterior and posterior ciliary nerves; 

 epa. anterior carotid artery; ep. epiphysis; g.cil. ciliary ganglion; inf. obi. inferior oblique; 

 lam. lamina terminalis of cerebrum; O.V. and VII, superficial ophthalmic branch of trigeminal 

 and facial; obi. sup. superior oblique; olf.b. olfactory bulb; opt. I. optic lobe; post.rect. posterior 

 rectus; r. op. prof, ramus ophthalmicus profundus of trigeminal; rs. sensory root of ciliary 

 ganglion; sup.rect. superior rectus; thai, thalamus; // to A', cranial nerves. 

 (After Young, Quart. J. Micr. Sci. 75.) 



ganglia. But the nerves also transmit motor-fibres to the muscles of 

 the jaws and branchial arches. They are in fact mixed roots, just as 

 we have seen that the primitive dorsal roots should be, carrying the 

 sensory fibres for the segment and motor-fibres for the non-myotomal 

 muscles (p. 36). 



