426 Ö. B. POLLAtlD, 



Fig. 10. Similar projection from below showing the terminal dis- 

 tribution of the buccalis and maxillaris superior and of the palatine. 

 The ethmopalatine articulation also is seen. The slight shading of the 

 cartilage in these two diagrams indicates the slight moulding over the 

 olfactory organ. 



Fig. 11. Reconstruction of primordial cranium to show especially 

 the tegmen cranii and the form of the snout. * marks the slight semi- 

 detached socalled labial cartilages , f denotes in outline where the 

 squamosal projection rests on the skull, ff where parietal and frontal 

 invade the orbitosphenoid. The extent of the craniospinal or opisthotic 

 projection is hardly seen. 



Fig. 12. Median section of the skull showing especially roots of 

 nerves. * marks the great foramen through which proceeds the vagus 

 and part of the jugular vein. Posteriorly above the parasphenoid runs 

 the canal for the anterior aorta. 



Fig. 13. View of posterior region of skull slightly from below, 

 especially to show relations of opisthotic process. The saccular pro- 

 tuberance is marked while above it is the important ridge *. 



Fig. 14. Suspension of shouldergirdle. To the supraclavicle are 

 mainly affixed the tendons of the muscles from the head to the shoulder- 

 girdle. 



Fig. 15. Palatal Region, especially to show dermal subrostral bone. 

 * marks the internal projection of the entopterygoid, f the space which 

 in the Frog becomes so extended. 



Fig. 16. Fin in natural position — Extensor or true ventral surface. 



Fig. 17. Fin turned forward to show palmar or true dorsal surface. 



Fig. 18. Fin dissected to show dorsal or flexor surface with the 

 nerve supply dividing into dorsal and ventral branches. 



Fig. 19. Diagram of aortic vessels — very diagrammatic, to show 

 precardiac artery. 



Fig. 20. Suspension of jaws. 



Fig. 21. Thymus in natural position. 



Fig. 22. Horizontal section of shouldergirdle and fin showing 

 relations of pro- and metapterygium to the shouldergirdle and the no- 

 ticeable form of the cartilage between the caracoid and scapular ossi- 

 fications. 



Fig. 23. The following sections were chosen from a number of 

 drawings. The left side is somewhat anterior to the right. The first 

 passes through the supratemporal mucous canal. It shows at * how 

 long the supraoccipital cartilage remains separate from the otic. Blue 

 indicates nerves, red arteries, dotted red veins, pale blue cartilage, yellow 

 perichondria! bone. 



Fig. 24. Section through the parietale, posterior portion of the 

 sacculus, and the basioccipital cartilage. On the right the suprapha- 

 ryngo branchial is seen passing up to articulate with the saccular wall 

 and the extent of ossification ^of that region is shown. The internal 

 cartilaginous canal of the extraordinarily long horizontal semicircular 



