On the Anatomy and JPhylogenetic Position of Polypterus. 4â5 



Explanation of the Figures. 



Tab. 27 — 30. 



!Fig. 1. General side view of head showing inhalent and exha- 

 lent apertures of the nose, the labial fold and extent of opercular flap. 



Fig. 2. View after removal of opercular series showing muscles 

 undisturbed and upper and lower branches to the mucous canal of the 

 Vllth nerve. 



Fig. 3. Further dissection especially to show jaw muscles and re- 

 lations of Vth and Vllth nerves. The nasal vestibule is also opened. 

 * represents the muscle at the angle of the jaw of unknown homology. 



Fig. 4. View after removal of jugular plate on one side. 



Fig. 5. View after removal of intermaxillaris ant. and post. The 

 paired branchiomandibularis or geniohyoid muscle is seen. In the coraco- 

 hyoideus is seen the tendon bone f ; * indicates the yellow mass possibly 

 the remains of a former gill. Behind are seen the sternal plates or in- 

 fraclavicles. 



Fig. 6. Ventral dissection, * indicate the curious yellow patches, 

 f = muscles of doubtful homology. 



Fig. 7. Diagrammatic representation of the anterior cranial nerves. 

 Third nerve blue, Trigeminal green, Facial red, Abducens black, Glosso- 

 pharyngeus black. Ampullae in the mucous canals are represented in 

 the nasal region. Though of course present elsewhere the sections did 

 not allow of their exact representation. At each ampulla the nerve 

 spreads out beneath a tall epithelium. * denotes a special branch of 

 the buccalis which supplies the mucous canal in the maxilla. 



Fig. 8. Vagus, hypoglossus and 4 spinal nerves. The roots of the 

 last three spinal nerves are not represented. 



Fig. 9. Projection from serial sections of anterior region showing 

 primordial cranium and some nerves. The ophthalmicus superficialis 

 and profundus are represented proceeding through the preorbital canal 

 and afterwards dipping into the nasal capsule. Cartilage blue , peri- 

 chondrial bone yellow. The olfactory nerve and organ are dotted in. 

 The split * indicates that incipient defection of cartilage met with in 

 Urodeles. Anteriorly the form of the snout is completely shown. 



