PLATE IV 



EYE MUSCLES, BRAIN, VALVULAR INTESTINE AND DUCTUS DEFERENS 



OF CHLAMrDOSELACHUS 



Figs. 10, 11 and 12. The eye muscles and their nerves, excepting the nervus abducens which innervates 

 the external rectus muscle. 



The explanation of the labels is combined with that for the next two figures. 

 After Hawkes, 1906, Figs. 4-6, pi. LXIX. 



Figs. 13 and 14. Dorsal and ventral views of lateral halves of the brain, showing roots of cranial nerves. 



H, optic nerve; III, oculomotor nerve; IV, trochlear nerve; V, VII, the united Gasserian and buccalis ganglia; VI, 

 nervus abducens; VII b., ramus buccalis; VTI h., truncus hyomandibularis; VUI, the ganglion of the eighth nerve; IX, 

 glossopharyngeal nerve; X, vagus nerve. 



A.B., anastomosing branch between the oculomotor and profundus nerves; C, ciliary branch of the profundus; Cer., 

 cerebellum; Hy., hypophysis; 1.0., inferior obhque muscle; L.I., lobi inferiores; Lin.Lat., lineae laterales or restiform 

 bodies; L.T"^., Locy's ner%'e (nervus terminalis); Oc.1,2,3, first three spino-occipital nerves; Op.S., optic stalk (cartilagO' 

 sustentaculum ocuH); Op.L., optic lobes; O.S., olfactory' stalk; Pro., profundus branch of fifth or trigeminal nerve; 

 Pros., prosencephalon; R.Ext., A and B, two parts of the rectus extemus muscle; R.In., rectus intemus muscle; R.In/., 

 rectus inferior muscle; R.S., rectus superior muscle; S.Ob., superior obHque muscle; S. V., saccus vasculosus. 

 After Hawkes, 1906, Figs. 7 and 8, pi. LXIX. 



Fig. 15. Valvular intestine sHt open to show the spiral valve and the thick muscular wall. 



After Gunther, 1887, Fig. 5, pi. LXV. 



Fig. 16. Lower part of left ductus deferens (vas deferens) opened longitudinally to show "annular" folds. 



After Giinther, 1887, Fig. 4, pi. LXV. 



