No. 470] 



UNITY OF GNATHOSTOME TYPE 



3. Membranous skeleton of Bdellostoma. (p. e.) 



4. Simple heart, (p. e.) 



5. Cranial aorta, (p. e.) (Subcordal aorta.) 



6. Peritoneo-pericardial cavity, (p. e.) 



7. Subintestinal vein. Ventral vein of amphioxus. (p. e.) 



8. Passage of subintestinal ^ Persistent subintestinal vein, 



vein through liver with- ^ which passes around portal 

 out capillary net (p. e.) L system. 



9. Gill arteries correspond to gill arches, not to hemibranchs. 



(P-) 



10. Vein from pronephros to right cardmal vein. (p. e.) 



11. Blood from anterior body walls passes into portal system. 



(p. e.) 



12. Contractile portal heart, (p.) 



13. Origin of carotids from lateral branchial commissure, (p. e.) 



14. Segmental disposition of somatic and renal artery and veins. 



(p.e.). 



15. Frequent anastomosis between post. card, veins, (p. e.) 



16. Inferior jugular veins, (p. e.) 



17. Large number of gills up f Functional branchial vessels; 



to 14. (p. e.) -{ functional branchial bars or 



t cartilages. 



18. Their reduction during ontogenesis, (p. e.) 



19. Functional pronephros, (p. e.) 



20. Absence of genital ducts, (p. e.) 



21. Brain, (p. e.) 



22. Cranial and spinal nerves — separation of motor and sensory 



branches, (p. e.) 

 When we compare these characters of a Craniate with the con- 



betwec^^^^^^ 



separated froni all tlic other Toi'iim a /oolnuirnl ^ap wlii^li we 



