Give the characteristics of the following with examples :
Sub phylum Vertebrata (Craniata)

Explanation

(i) In these animals, the notochord is replaced by vertebral column.
(ii) Head is well developed and brain is protected in the cranium.
(iii) Endoskeleton is either cartilagenous or bony.
(iv) Some chordates are jaw-less (Agnatha) whereas some are with jaws (Gnathostomata).