DISSECTION OF THE SHARK 27 



Draw the contents of the orbit as seen from above, including 

 the eye, its muscles, and all nerves which enter the orbit. 



13. The eyeball. — Remove the eyeball from the orbit by cut- 

 ting all of its attachments, and dissect the eye. Open the eye- 

 ball by a cut around the equator between the cornea arid the 

 optic nerve. In the inner half of the eyeball note the three 

 coats — the tough sclerotic, the pigmented choroid, and the 



Fig. 5B. — An analysis of the cranial ganglia of Squalus acanthias 

 ("pup" stage). The somatic motor roots are omitted; cf. Fig. 5A. For 

 the significance of the conventional symbols see the accompanying legend. 



Abbreviations 



ac-lat., area acustico-lateralis of brain. 



buc.VII, ramus buccalis VII. 



cbl., cerebellum. 



dors.X, ramus dorsalis X. 



g ac, ganglion acusticum. 



g hue., ganglion of ramus buccalis VII. 



gen., ganglion geniculi VII. 



gg., ganglion gasseri. 



g gl., visceral ganglion of IX. 



g ll.X, ganglion of ramus lateralis X. 



g mde., lateralis ganglion on hyomandibular trunk. 



g op., ganglion of ramus ophthalmicus profundus. 



g os.VII, ganglion of ramus ophthalmicus superficialis VII. 



g spt.IX, ganglion of ramus supratemporalis IX. 



g spt.X, ganghon of ramus supratemporalis X. 



g X.l to g X.4, visceral sensory ganglia on the vagus. 



hy.VII, ramus hyoideus VII. 



IX, nervus glossopharyngeus. 



IX r., roots of nervus glossopharyngeus. 

 lat.X, ramus lateralis X. 



max.V, ramus maxillaris V. 



md.V, ramus mandibularis V. 



mde.VII, ramus mandibularis externus VII. 



mdi.VII, ramus mandibularis internus VII. 



mes., midbrain. 



op.V, ramus ophthalmicus profundus V. 



os.V, ramus ophthalmicus superficialis V. 



os.VII, ramus ophthalmicus superficialis VII. 



pal.VII, ramus palatinus VII. 



rest b., "corpus restiforme" (anterior end of acustico-lateral area). 



spt.IX, ramus supratemporalis IX. 



spt.X, ramus supratemporalis X. 



VII r., roots of facialis proper. 



VII r 11., lateral line roots of facialis. 



X r., roots of vagus proper. 



X r 11., lateral line root of vagus. 



X.l to X.4, first to fourth branchial rami of vagus. 



